If Marvel Studios and its creative teams have been consistent about anything, it's in talking around the possibility of a sequel to The Incredible Hulk. Despite Mark Ruffalo's take on Dr. Bruce Banner becoming a fan-favorite in The Avengers, the largest and meanest of Earth's Mightiest isn't quite bankable enough for a solo outing.
Instead, like fellow Avengers Black Widow and Hawkeye, Hulk is a key supporting character, and so far his stories have been exclusive to the Avengers movies. That changes in Phase 3 of the Marvel Cinematic Universe when, after all the other Earthly characters of the franchise show up in Captain America: Civil War, the remaining two - Thor and Hulk - return in 2017's Thor: Ragnarok.
Since long before Avengers: Age of Ultron opened in theaters, rumors dating as far back as early 2013 pointed towards Marvel using the Joss Whedon-written and directed sequel as a launchpad to a Planet Hulk adaptation that would launch the brute into space. Eventually, just like in Marvel Comics, Banner/Hulk could return to Earth seek vengeance in a World War Hulk style of story. Marvel Studios boss Kevin Feige added that he believes Hulk could carry his own new movie and that these two aforementioned events from the comics are "cool" stories of interest to him and the studio.
That hope was quickly dashed however by Ruffalo and Whedon, and later completely eradicated when Marvel laid out their entire Phase 3 schedule in October of 2014. Hulk was nowhere to be found and Feige said himself, Planet Hulk wouldn't be the right move for a standalone feature because they'd want to use Ruffalo on screen more instead of just the CGI Hulk.
And then everything changed.
Reports began surfacing several months ago that Marvel was planning on using Thor: Ragnarok as a way to bring back the Hulk, and to do so off-planet... just like Ruffalo hinted at once again last year. We knew Thor 3 would finally focus less on Earth and explore more of the cosmic side of the lore, and as additional reports confirmed that Ruffalo would be teaming up with Chris Hemsworth for a "buddy adventure" film, speculation was once again sparked that Marvel could be taking a page from the books of Planet Hulk after all.
The last time we saw Hulk was in the final act of Avengers: Age of Ultron when he stole the team's Quinjet and flew away. We didn't know where but early rumors about the Avengers 2 script pointed towards it launching Hulk into space. That didn't make the final cut and it was left ambiguous as to give Marvel more options as they plan for the future. And planned they have, according to the latest rumor from Geek which claims to have sources revealing more plot details about Thor: Ragnarok. Potential spoilers ahead.