Who's the captain now? If you watched the post-credits scene in Avengers: Infinity War, you know it's Captain Marvel (Brie Larson).
In the Infinity War scene, Nick Fury (Samuel L. Jackson) and Maria Hill (Cobie Smulders) find themselves in the middle of the Thanos-sparked chaos as half the universe's population disappears. Fury manages to use his pager and apparently sends a message to Captain Marvel just as he, too, disappears into dust. Since her film arrives before the next Avengers films, it would seem she's got an important role to play in Avengers 4, possibly saving the universe from an invasion of the Skrulls.
And when Infinity War was released on digital in August, a keen-eyed Reddit user pointed out that one of Thanos' children, Cull Obsidian, was seen wearing a piece of cloth with Captain Marvel's colors and design on it. What that means is yet uncertain, but it adds even more anticipation to the mix.
Captain Marvel? Not exactly the best-known superhero ever. But her film will be the 21st in the Marvel Cinematic Universe, and if she's going to get that kind of post-credits attention, fans had best brush up on her dossier before her film comes out.