One of the more exciting shows coming to Disney+ is Marvel's What If series, which is based on the popular comic that put characters into new situations that are told in one-shot stories. The fact that this will be an animated series could show some promise and the first episode is going to please every kind of MCU fan.
Peggy Carter, who many see as Captain America's one true love, is going to take the spotlight as she takes the super soldier serum instead of Steve Rogers. This will result in Peggy becoming Captain America, which is a really neat concept, though not the most original. Don't get me wrong, it will be awesome seeing this in animated form, it's just that other forms of media have explored this before, like the Exiles comic series and the mobile game Marvel Contest of Champions.
Don't worry Steve fans, he won't be a worthless character in this episode. Rogers will receive a suit of armor from Howard Stark, which is eerily similar to the Bullet Points comic book that J. Michael Straczynski, so it looks like these episodes will be borrowing a lot from Marvel's alternate universes. This should make for some fresh stories that will take comic book fans interested.
Marvel's What If series doesn't have a proper release date but it's expected to come out in the same year as Disney+ streaming service.