At the end of Captain Marvel, Carol gives Nick Fury a
pager, upgraded to allow him to contact her across at least a couple of galaxies, for “emergencies only”.
She also leaves
the Tesseract, from which her powers were derived,
on Earth with him. In the post-credits scene of Avengers: Infinity War, he uses
the pager to contact Carol, presumably to ask for help with the small matter of loads of people dissolving out of existence.
However, weren’t there earlier occasions that called for the same action? Specifically:
the theft of the Tesseract, and the subsequent use of it to allow an alien invasion of New York led by an Asgardian, in The Avengers?