The Captain Marvel movie had a lot of heavy lifting to do when it came to the Marvel Cinematic Universe as a whole. It wasn’t just a prequel to one movie, but several. It told the backstories of Nick Fury, Phil Coulson, the Tesseract, the “Avengers” name and more. And, of course, it introduced Captain Marvel, aka Carol Danvers, herself.
However, audiences had previously received a teaser for Captain Marvel via the end credits scene of Avengers: Infinity War. In it, Nick Fury is seen hitting a button on an old pager as chaos erupts all around him. That action, it turns out, will summon Captain Marvel at a time of need.
After Infinity War, though, some fans questioned why Nick Fury never tried pressing that pager button before, as Earth has certainly needed help in situations prior to that one. Marvel Studios boss Kevin Feige subsequently answered that question in an interview with the website SlashFilm in March 2019.