After the release of The Winter Soldier this April, all roads lead to the Avengers: Age of Ultron. In the new issue of Total Film, Kevin Fiege goes on to talk about how Black Widow's storyline will finally be revealed in the Avengers sequel next year and how it could possibly lead into a solo film.
“We start filming the next Avengers film at the end of March. Widow’s part in that is very big. We learn more about her past and learn more about where she came from and how she became who she became in that film. The notion of exploring that even further in her own film would be great, and we have some development work with that.”