This is the splash page from New Mutants #1. I love this page because it introduces you to the characters without being heavy handed about it, and without regard to their mutant abilities–it’s just about character.
But this wasn’t their first appearance. The team first appeared in Marvel Graphic Novel #4 by Chris Claremont and Bob McLeod, and the book sold so well they got a series.
That oversized volume hit the stands on September 7, 1982.