We've heard a lot of conflicting reports about Brie Larson's Avengers: Infinity War status with many fans theorising that Marvel Studios will be using that movie to introduce her to moviegoers for the first time. While it is, of course, possible that she'll show up in an after-credits scene of some sort, it's now been confirmed that she won't be assembling with Earth's Mightiest Heroes until Avengers 4 in 2019.
During an on-set interview for Avengers: Infinity War, Joe Russo was quick to praise Brie Larson but made it clear that she won't be blasting her way into that movie when it's released on April 27th.
"If it's not, it is official now," Joe Russo said in regards to Carol Danvers first joining the team in Avengers 4. "I think Captain Marvel's got a great outfit in this film." Considering the fact that Captain Marvel is set primarily in the 1990s, it's not clear if her solo movie or Avengers 4 will deal with her arrival in the present day but it makes sense for it to be either one given each of their cosmic settings.
Regardless, we can clearly expect Captain Marvel to go some way in setting up the events of Avengers 4 and can forget about the character making a cameo appearance of any sort a month from now.