The gold standard of super-heroes was Superman, and the best of the war comics featured Sgt. Rock....
...so, here is a simple tale of the time these two characters met under a cover by Ross Andru and Dick Giordano!
The Miracle Man Of Easy Company
To save Paris, Superman flew into space above it....and disappeared when the bomb went off. Superman awoke on the ground in Paris of 1944, seeing two Nazi soldiers taking off their American soldier disguises, yet found...he could not remember his own name!
Superman answered enough of Easy's tests to lay some of their fears to rest (but, now Sgt. Rock was unsure whether this new Tag-Along would be able to perform under combat). Soon, the troop was set upon by a Tiger tank, with Tag-Along holding the bazooka, which he was ready to fire....but didn't (Superman had a code against killing). In frustration, he hit the ground, which caused a chasm, that engulfed the tank (Superman didn't know his own strength).
It was in the next issue where Superman found out who planted the bomb, all in a team-up with Hawkman...all in a wonderful tale summarized here (along with a few other the Hawkman and Superman team-ups!).
Why wouldn't Sgt. Rock and Easy know super-heroes? (While on Earth-2, super-heroes were contemporaries of World War II, on Earth-1, Superman was one of the first heroes, who first appeared only relatively recently....with super-heroes only the things of comic books!).