back when DC and Marvel used to be on much friendlier terms - DC being teased as “The Distinguished Competition” - crossovers between companies happened here and there, ‘bout all the way up to the late 90s, ‘round when Quesada takes over Marvel. that’s a whole story in itself.
one of my favorite crossovers between the two is Superman Vs. The Amazing Spider-Man, 1976, written by the very underrated Gerry Conway, with pencils by Ross Andru, Neal Adams, and a dash of John Romita Sr. and featuring this fantastic page right here.
one of the best marvel/dc crossovers was “Superman VS. The Amazing Spider-Man” by legendary spider writer Gerry Conway, which ends up at one point with a situation where an enraged pete punches clark’s chest so hard and for so long that he ends up breaking his own hands