Warning: This article contains SPOILERS for Avengers: Endgame.
After the events of Avengers: Endgame, what is the future of Iron Man and his alter ego Tony Stark in the MCU? Joe and Anthony Russo's mega-blockbuster not only concludes the macro story spanning the first 22 films of the Marvel Cinematic Universe but it also provides a fitting an poignant end to Robert Downey, Jr.'s billionaire superhero who started it all. When Iron Man launched the MCU in 2008, no one dreamed that a vast and diverse universe of billion-dollar hit films would be its result (as Tony Stark's final speech at the conclusion of Avengers: Endgame alludes to). Robert Downey, Jr's. Tony Stark has been the centerpiece - or rather, the living arc reactor - of the MCU by starring in three Iron Man films, four Avengers films, and Captain America: Civil War and Spider-Man: Homecoming.
Avengers: Endgame proved to be Tony Stark's swansong. After suffering their greatest defeat in Avengers: Infinity War, Iron Man helped lead the Avengers to a definitive victory against Thanos in Avengers: Endgame's final battle, and they restored the lives of half of all beings in the universe the Mad Titan erased from existence in the Decimation. In the end, Stark used the Infinity Stones to snap Thanos and his forces to dust, a final sacrifice that led to Iron Man's death. But this is the MCU and even death isn't necessarily final. It's certainly hard to top a death like Tony's in Avengers: Endgame and, after 11 years wearing the armor, no one could blame Downey or Marvel Studios if they wanted to let Tony rest for a while; therefore, a resurrection in the near future would be cheating and definitely feel cheap.
Still, despite Tony book-ending the first 22 movies by declaring "I am Iron Man!", the Golden Avenger could still keep appearing. After all, the Marvel franchise is a comic book movie universe and it's hard to imagine the MCU will be without Iron Man forever. Tony Stark is such an integral part of the MCU that his influence will continue on even after his death, but Iron Man could still keep appearing in other ways. And, as Avengers: Endgame's time travel shenanigans illustrated, there are various means that both Tony Stark and/or Iron Man could be seen again, even if the mainline incarnation of Tony is dead.
Tony Stark Is A Hologram - Could That Be Robert Downey, Jr.'s Return Clause?
Barring an outright resurrection, Tony could simply appear as a hologram in future films. Avengers: Endgame already established this was possible; Tony recorded a hologram message right before the heroes attempted their time heist gambit. In case it failed, Tony wanted the hologram to serve as a final goodbye to his love Pepper Potts and their young daughter Morgan, and it played at his funeral. So the easiest way to keep seeing Tony Stark in the MCU would be for Downey to occasionally reprise his role as a holographic version of himself (and continue collecting hefty paydays).
After all, Tony has always been reliant on A.I.s; Jarvis and Friday were his constant companions as Iron Man. It's not a stretch to imagine that Stark would upload his own personality as an A.I. to keep his genius alive (this is certainly believable given Tony's infamous ego). In fact, if anyone else were to wear Iron Man's armor, it would make sense for Tony Stark to be the onboard A.I., and this would also create a lot of comedy for whoever is stuck with Tony second guessing them and fast-talking in their ear.
There Could Be Another Iron Man
While Tony Stark (and Robert Downey, Jr.) may be irreplaceable, Iron Man isn't. In fact, there have technically been two Iron Men in the MCU ever since James Rhodes took one of Tony's suits in Iron Man 2. As War Machine (he was also called Iron Patriot in Iron Man 3), Rhodey has been an Avenger ever since the end of Avengers: Age of Ultron; in fact, after Team Cap became fugitives in Captain America: Civil War, the Avengers were comprised of Iron Man, War Machine, and Vision, all Stark loyalists who are variations of Iron Man. The fourth member would have been Peter Parker wearing Iron Spider armor before the kid decided to remain a friendly-neighborhood Spider-Man.
War Machine and Spider-Man will continue to wear StarkTech suits, but someone new could wear the red and gold Iron Man armor in Tony's wake. One possible choice is Harley, the kid Tony befriended in Iron Man 3. Now grown up, Harley was one of the mourners attending Tony's funeral in Avengers: Endgame, and this could be a clue that he could be hired to be the next Iron Man.
Rescue Is Unlikely To Be Iron Man
Though Pepper Potts has been a female version of Iron Man twice, she's unlikely to take over Tony's job as a superhero. Pepper wore one of Tony's suits in Iron Man 3 and Tony made her a black, purple, and chrome suit of her own, which she wore in the final battle against Thanos in Avengers: Endgame. (In the comics, Pepper calls herself Rescue when she wears her armor.) Still, those were specific occasions where Pepper played superhero and not something Ms. Potts is inclined to do full-time in the MCU. With Tony gone, Pepper has to raise Morgan alone as well as continue to be CEO of Stark Industries.
Furthermore, Gwyneth Paltrow has left the MCU, stating, "I’m a bit old to be in a suit and all that at this point." Although, the Academy Award-winning actress added, "If they said, ‘Can you come back for a day?’ I will always be there if they need me.” So Pepper Potts could certainly reappear in the MCU, but not as Rescue or as a new Iron Man.
Will Morgan Stark Be Iron Man?
It would be fitting if Tony's daughter Morgan wore Iron Man's armor one day; this was even teased when she donned her mom's Rescue helmet early in Avengers: Endgame. The catch, though, is Morgan is currently 4-5 years old in the current MCU timeline set in 2023. Even if she inherits her father's genius-level intelligence, she can't wear a suit and be Iron Kindergartener. If Morgan Stark does become Iron Man in today's MCU, it would have to be a grown-up, future version of her that time travels back to the MCU's Phase 4 era. This sounds complicated, but Avengers: Endgame has already opened up possible alternate branches of the MCU timeline and an adult Morgan (who could solve time travel like her dad did) could come back from a possible future.
The MCU also has begun teasing the possibility of a Young Avengers group with Hawkeye training his daughter Violet in archery at the start of Avengers: Endgame (this also nods towards the anticipated Hawkeye Disney+ series headlined by Clint Barton and Kate Bishop) and a Young Avengers team could be a place for a future Iron Man. It's also possible the adult Morgan Stark is indeed the role Katherine Langford was supposed to play in Avengers: Endgame when it was announced she was cast. But until Marvel reveals plans (if any) for Morgan Stark, Tony's precocious daughter is still too young to be Iron Man right now.
What About Riri Williams As Ironheart?
In recent Marvel Comics, a 15-year-old genius engineering student named Riri Williams briefly became Iron Man and Tony Stark's protege. Riri was enrolled in MIT and built her own Iron Man armor, which led to Tony Stark bringing her aboard to be Iron Man with himself as the A.I. in her armor. Riri has since adopted the codename Ironheart and is wearing different suit design, but could Riri Williams debut in the MCU?
The link to MIT is already there for Riri to jump into the movies; thanks to the September Foundation, Tony gave millions of dollars in grants to MIT students in Captain America: Civil War - Riri could be one of those recipients and, with a similar origin story of building her own suit, could be brought aboard to be the new Iron Man. A future MCU movie could replicate the comics' format of Riri wearing the suit while being mentored (and frustrated) by Tony's A.I.
An Ultimate-Style Reboot of the MCU Could Bring Back Tony Stark
The most radical way to bring back Tony Stark without resurrecting the original version who died in Avengers: Endgame would be by rebooting the MCU into the Ultimate Universe. In 2000, Marvel Comics launched an alternate Ultimate Universe with their core characters like Spider-Man, the X-Men, and the Avengers (renamed the Ultimates) rebooted into their own reality. In 2015, the Ultimate Universe was merged with the main Marvel Universe at the conclusion of the Secret Wars storyline. In fact, a Secret Wars movie is something the Russo Brothers and Avengers: Endgame's screenwriters have said they would be interested in making.
With Avengers: Endgame introducing branching timelines into the MCU, this could open the door to a possible rebooted Ultimate MCU movie universe - and a new version of Tony Stark. Whether a new Ultimate Iron Man is younger (either recast or played by a digitally de-aged Robert Downey, Jr.) or portrayed by a new actor entirely, an Ultimate MCU could be a way to have the original six Avengers come back without reversing the endings they received in Avengers: Endgame. While this is certainly a long shot idea, Avengers: Endgame proved anything is indeed possible in the MCU. One way or another, Iron Man will likely return, the question is simply when and how?