If we had to choose between the two, we’d guess that Brie Larson might appear in one of the Avengers movies, though with Avengers: Infinity War basically wrapped, this might mean Captain Marvel is on the docket for the ultra-mysterious Avengers 4.
Best we can tell, Brie Larson’s debut film — Captain Marvel — hasn’t started filming yet (even though it’s due in theaters March 2019).
Instead, Marvel has been toiling away on Peyton Reed’s Ant-Man and the Wasp, and the Russo Brothers, Joe and Anthony, have been working on back to back Avengers movies.