We all knew Captain Marvel would be coming out after Avengers: infinity War but most of us didn't realize how important she would be until the end of the film. Nick Fury managed to contact her before turning into dust, which made many fans go giddy. Why Fury would think of contacting this hero after a life-ending threat shows that she must be pretty powerful and we'll get to see the full extent of her power next March.
During an interview with Marvel.com, Captain Marvel Prelude writer Will Corona Pilgrim was interviewed about the comic, which heavily focused on Nick Fury. By the end, Pilgrim was asked why Fury would call Captain Marvel at his time of death, a question we had all been asking. Pilgrim actually gives a pretty great answer; because she is the biggest gun Earth has against Thanos.
Pretty much everyone who has worked in the MCU has confirmed that Carol Danvers is the most powerful superhuman right now. Some fans might take umbrage with the fact that she might be stronger than Thor but hey, he almost killed Thanos so it's not like the God of Thunder is a pushover.
Captain Marvel will be an origin film that details the character's past and shows just how she came to Earth. From what we've seen in the trailer, Danvers is more familiar with the Kree part of her heritage and the movie will show how she feels being back on Earth.
Captain Marvel comes out on March 8, 2019. Avengers 4 hits theaters on May 3, 2019.