The Hulk returned along with the rest of the original Avengers in Avengers: Endgame, but what does his future in the Marvel Cinematic Universe look like now? Hulk is unique among the members of Marvel Studios' flagship superhero team, in that he's the only character for whom Marvel cannot make solo movies (since those rights belong to Universal Pictures). Despite this, Bruce Banner has managed to eke out an intriguing character arc through ensemble movies and his "guest" appearance in Thor: Ragnarok.
Things took a turn for Bruce in Avengers: Infinity War when, in the Avengers' most crucial battle yet, the Hulk refused to come out and play. Then, in Endgame, things got even stranger when the Avengers sought out Bruce and found that he had managed to merge his two personalities to create Smart Hulk - all of Bruce Banner's science genius, wrapped up in Hulk's brawny green body. After Thanos was finally defeated for good, Hulk's final scene involved sending Captain America back in time to replace the Infinity Stones, and Bruce somewhat faded into the background as Cap got his emotional send-off.
This leaves Hulk's future in the MCU pretty open. With Iron Man and Black Widow dead, Steve Rogers now an old man, Hawkeye returned to his family, and Thor off in space with the Guardians of the Galaxy, it looks like Hulk is the last original Avenger left at HQ - and he too might go off and do his own thing (as the Avengers usually do in between their team-up movies). Out of all the original Avengers, however, Hulk's future in the MCU Phase 4 might be the most complicated.
Marvel Can't Make Solo Hulk Movies
In the same year that Iron Man kicked off the MCU, Universal Pictures released an MCU movie as well: The Incredible Hulk, starring Edward Norton as Bruce Banner. It served the character well as an origin story, but outside of occasional references (like Bruce recalling the time he "broke Harlem") and the eventual return of William Hurt as Thunderbolt Ross, it's easy to forget that Incredible Hulk is an MCU movie. Not only was the role of Bruce Banner soon recast with Mark Ruffalo, there also hasn't been a standalone Hulk movie since.
In theory, Marvel Studios could add another solo Hulk movie to the MCU slate... but it's very unlikely to happen. Universal has a "first refusal" option on Hulk's movie rights, which means that if Marvel wanted to make a Hulk solo movie, it would first have to offer Universal the option of distributing it (similar to how Sony Pictures distributes the MCU Spider-Man movies). That's a major disincentive for Marvel, since it means splitting the profits on any Hulk solo venture, so instead the studio came up with a workaround: featuring Hulk as a supporting character in team-ups and other character's movies. So far, this approach has worked surprisingly well, allowing Marvel to give Hulk a three-movie arc without actually giving him a Hulk movie.
Avengers: Endgame Ends Hulk's Three-Movie Arc
In 2017, Mark Ruffalo revealed that Thor: Ragnarok - in which Thor finds Hulk living a new life as a gladiator on the planet Sakaar - was the start of a new Hulk trilogy, with a clear character arc through three ensemble movies. As Ruffalo explained, Marvel Studios boss Kevin Feige asked for his insight on what direction the character should take, and hatched a plan for executing a three-act story through Hulk's next three movie appearances:
"Kevin pulled me aside before this, and said, 'If you were gonna do a... if we were going to do a standalone Hulk movie, what would it be?' And I said, 'I think it should be this, this, this, and this and this, and ends up like this.' And he's like, 'I love that. Why don't we do that in the next three movies, starting with Thor 3 and then we go into Avengers 3 and 4.'"
Avengers: Endgame marked not only the culmination of a story arc that the MCU has been building since 2012's The Avengers, but was also effectively the final act of Hulk's current character arc - and it wraps it up quite neatly. The "Hulk trilogy" began with Ragnarok, a movie where Hulk was keeping Bruce suppressed, and then continued with Infinity War, a movie where Hulk refused to come to the surface. By uniting those two extreme alter egos, Avengers: Endgame created, as Smart Hulk put it, "the best of both worlds." However, given that the struggle between his mild-mannered scientist side and his green rage monster side has been a core part of Bruce's character up until Endgame, we now have to wonder what conflict will replace that struggle in the MCU Phase 4.
Mark Ruffalo Still Has MCU Movies On His Contract
One of the upsides to Hulk not getting his own trilogy of solo movies (like Captain America, Thor, and Iron Man) is that Ruffalo has been working through his six-movie contract with Marvel at quite a sedate pace. Ruffalo has so far starred in The Avengers, The Avengers: Age of Ultron, Thor: Ragnarok, and Avengers: Infinity War, so after Avengers: Endgame he's still committed for one more movie.
By contrast, some MCU actors came to the end of their six-movie contracts with Endgame - most notably, Captain America actor Chris Evans, and Thor actor Chris Hemsworth. While Hemsworth seems amenable to continuing as Thor in the wake of Thor: Ragnarok's success, Evans has openly said that Avengers: Endgame is his last MCU movie, and Endgame also said a tearful goodbye to Robert Downey Jr.'s Iron Man. As the biggest stars of the MCU are departing, it will make room for the more sidelined characters to move into more prominent roles.
Hulk Is An Easier Character To Keep Around Than Captain America Or Iron Man
Hulk's relative lack of solo movies has added longevity to the character in ways that go beyond Ruffalo's contract with the studio. Like other "supporting Avengers" - Black Widow and Hawkeye being the obvious examples - Hulk still has a great deal of unexplored potential within the MCU. Iron Man has enjoyed three solo movies, an Avengers movie largely based around the consequences of his arrogance (Age of Ultron), a supporting role in Spider-Man: Homecoming, and what was basically a co-lead role in Captain America: Civil War. He was also one of the most prominent superheroes in Avengers: Infinity War, and finally got to enjoy a suitably heroic death in Avengers: Endgame.
By contrast, we've barely scratched the surface of Hulk's potential in the movies. Between all the various threats to the planet, Bruce's romance with Black Widow has been sidelined to the point of near non-existence, with the two sharing little more than a greeting in Avengers: Infinity War. Admittedly that particular subplot has had a lukewarm reception from fans, but that's mainly because it's been given so little room. Sure, Black Widow was killed off in Endgame, but she's returning for a solo movie in Phase 4 and it wouldn't be at all surprising if Marvel found a way to bring her back to life.
On a practical level, Hulk is also easy to keep around because whenever the "Big Guy" is in play, the character is entirely CGI. "The Hulk" - as he usually appears on posters and in trailers - is most recognizable in his transformed state. The role has already been recast once, and if Ruffalo ever does decide that he's sick of playing the role, Marvel could quite feasibly recast the character again.
Hulk Stories That Could Be Explored After Avengers: Endgame
There are countless great Hulk comic arcs that many fans would love to see, but we have to keep in mind the fact that Marvel Studios is extremely unlikely to make a Hulk solo movie. The character's Planet Hulk arc was partly incorporated into Thor: Ragnarok, but was necessarily stripped down to the point that the only plot elements included were Hulk hitting a wormhole and crashing on Sakaar, and Hulk taking up a new life as a gladiator.
Just as Hulk was a supporting character in Ragnarok, his future in the MCU after Avengers: Endgame will most likely consist of ensemble movies and providing back-up in other characters' solo movies. With that in mind, the most obvious place for Hulk to crop up next would be in the planned Black Widow solo movie, as a love interest/backup for Natasha Romanoff - but if the rumors of Black Widow being a prequel movie prove accurate, the continuation of Bruce and Natasha's romance could be foiled again.
Interestingly, Hulk has now joined Thor in straddling the barrier between the cosmic and Earth-based worlds of the MCU. As a scientist, Bruce may well have gotten a taste for interstellar travel, and as such could crop up in cosmic stories like Guardians of the Galaxy 3 or even a sequel to Captain Marvel. Or, assuming all goes smoothly with Disney's acquisition of Fox, Hulk could help to usher in the Fantastic Four whenever they get their first MCU movie. The strength of the MCU's Hulk is that, because he's been established as an ensemble character, he can jump from franchise to franchise without it feeling unnatural - and fans can get a real kick out of say, Bruce hanging out with the Guardians, or Hulk getting into a brawl with The Thing.
The post-Avengers: Endgame future is looking uncertain right now, but as a character who has been around since the very start of the MCU, Hulk could be just the giant green rage monster we need to usher in the next phase of stories.