Newly-released concept art from The Wakanda Files book reveals Betty Ross (Liv Tyler) working with Mark Ruffalo's version of Bruce Banner.
Marvel Cinematic Universe concept art features Betty Ross working with Mark Ruffalo's Bruce Banner. Played by Liv Tyler in 2008's The Incredible Hulk, the character was introduced as the love interest of Edward Norton's version of the titular character. Since the Hulk was recast, however, Betty has yet to be been again in the MCU despite her father, Thunderbolt Ross, regularly factoring in other films, including a slated appearance in Black Widow.
Like the recasting of War Machine from Terrence Howard to Don Cheadle, Marvel Studios treats Ruffalo's version of the Hulk simply as a continuation of the origins story of Norton's version. Given this, it doesn't make sense that the franchise has yet to bring back Betty Ross for more than 10 years now, especially since Banner has turned his image around and is now a beloved public figure as seen in Avengers: Endgame. A new concept art, however, might be teasing her eventual return to the MCU.
Shared by a Reddit user with the handle u/OhGawwDuhhh from the book The Wakanda Files is an image of Betty and Bruce working in a lab. Instead of looking like Norton, however, Hulk's alter-ego resembles Ruffalo's version. According to the user, this image was supposed to depict their professional relationship before Bruce's gamma radiation exposure.
At this point in the MCU, Marvel Studios is already slowly transitioning to a new batch of heroes, with most of the original Avengers getting their respective replacements. Unlike some of his fellow founding heroes, Bruce Banner remains in active duty as Smart Hulk following the Infinity Saga. While it's unclear what the future lies for him after the events of Endgame, the character can be quickly incorporated in any future stories. Ruffalo previously revealed that there have been talks for him to appear in the upcoming She-Hulk Disney+ series which will introduce Jennifer Susan Walters, but no official word about it thus far.
With Bruce Banner and the Hulk already one entity in Smart Hulk, there's really no obvious compelling story left for the character except for this lingering question about his relationship with Betty Ross. It's not like he has remained faithful to her over the years with Bruce starting a short-lived affair with Black Widow which ultimately didn't go anywhere. It also doesn't seem like Bruce is keen on at the very least finding her, if anything, he might not even be interested in starting another romance with anyone again. But Marvel Cinematic Universe can't simply ignore this nagging mystery, especially since Thunderbolt Ross continues to be actively involved in the franchise.