Scarlett Johansson is currently busy promoting her upcoming solo Black Widow film. The film will take place before the events of Avengers: Endgame. Johansson's role as Natasha Romanoff has long been a fan favourite from the Marvel Cinematic Universe.
Going forward the MCU is now looking towards adding newer members into the roster of superheroes. After Disney acquired Fox Marvel now has rights over its X men characters once again. Kevin Feige who is the head of the MCU is busy figuring out a way to introduce the X men and mutants into the long line of Marvel films.
Now it seems like fans finally have a sneak peek at how Marvel is attempting to bring the mutants home. While promoting her film in a recent interview Scarlett Johansson called Hulk played by Mark Ruffalo a mutant. She said, "None of us knew if this movie was going to work. It seemed crazy." She went further, explaining, "There's a Nordic God, there's the Tony Stark character the billionaire playboy, and then there's a mutant scientist who's got an anger management problem." Johansson also spoke about the uncertainty of whether The Avengers would be a success, saying, "This sounds like people are either going to love it, or it's going to be a mess."
Fans quickly jumped to conclude that this might be a hint at how Marvel is planning to introduce the Mutant line of superheroes into its main canon. However, until Kevin Feige himself confirms any of these theories they will remain as theories.