Mark Ruffalo has no idea whether or not Iron Man 3. Despite this recurring role in the larger series, Ruffalo's Hulk has never been given a solo movie of his own.
The Hulk's history on the big screen is a curious one. After a less-than-loved adaptation by Ang Lee in 2003, the character headlined the second-ever MCU movie, 2008's The Incredible Hulk. That film starred Edward Norton in the role, but he was replaced with Ruffalo after the film's release, Avengers: Endgame.
During an interview on The Graham Norton Show (per gave up his shield to live out his life with Peggy Carter. While many characters in the film were given definitive endings, Hulk, on the other hand, is still very much a part of the ongoing MCU.
But the biggest unknown at the moment is how the MCU will handle its future team-ups, a decision that will likely be the deciding factor in Hulk's potential return. There's currently no story reason to continue Banner and Hulk's journey, and with all his closest friends either dead, retired, or off exploring the cosmos, there's not much reason for anyone to call him in. What the Hulk needs then, is the next big threat where the new Avengers have no choice but to bring him back, but who knows how long it will take the MCU to build up to that.
Source: The Graham Norton Show (via comicbook.com)
