Sebastian Stan admitted that he would be interested in doing a Winter Soldier solo movie, if the opportunity presented itself.
While at the premiere of Avengers: Infinity War, Stan talked to Variety about the infinite potential Marvel movies have when it comes to spinoffs. He believes that after each film, there is enough story to potentially revisit some of the characters, which is how he envisions a Winter Soldier solo film working.
Citing that he learns something new about his character each time he plays him, Stan seems to be interested in revisiting the past. The character has mostly grown beyond his Winter Soldier persona, but a film that allowed time to revisit some of the stuff we haven't seen before would make Stan "down, 100%" for a Winter Soldier movie.
Now that Bucky has returned from suspended animation just in time for Infinity War, he has largely given up the Winter Soldier identity. However, a solo film could easily go back in time, much like how Warner Bros. did with Wonder Woman in 2017.
Directed by Joe and Anthony Russo, Avengers: Infinity War stars Robert Downey Jr., Chris Evans, Chris Hemsworth, Mark Ruffalo, Jeremy Renner, Scarlett Johansson, Anthony Mackie, Paul Rudd, Elizabeth Olsen, Tom Holland, Benedict Cumberbatch, Chadwick Boseman, Chris Pratt, Zoe Saldana, Dave Bautista, Bradley Cooper, Vin Diesel, Tom Hiddleston, and Josh Brolin. The film arrives April 27.