Superman does not appear in Marvel comics, but Clark Kent...

...I mean Ken Clark for legal purposes does!

Clipped from Marvunapp: Clark as seen on Earth-616 is an alternate dimensional counterpart of Superman. DC exists in a separate dimension/continuity than Marvel. Technically, Marvel and DC are within different Megaverses, but within the same Omniverse.  On Earth-616, there is no evidence that Clark is anything more than a mild-mannered reporter, though there is nothing to refute that, either...other than legal issues, copyright, etc.!  Also, though the homage is undeniable, I'm fairly certain in the Marvel Universe that he has only been named as Clark, and not specifically as "Clark Kent."
So, with that in mind, let the games begin. --Snood.

Appearances:
X-Men I#98 (April, 1976)
Marvel Team-Up I#79 (March, 1979)
Captain America I#260 (August, 1981)
Avengers I#228 (February, 1983)

Thor I#341 (March, 1984)

Secret Wars II#7 (January, 1986)

Uncanny X-Men Annual#10 (1986) 

Avengers I#296 (October, 1988) 

Excalibur I#8 (May, 1989)

Uncanny X-Men#245 (June, 1989)

Amazing Spider-Man Annual#23 (1989)

Power Pack I#53 (July, 1990)

Avengers I#325 (October, 1990)

Avengers I#327 (December, 1990)

Web of Spider-Man#75 (April, 1991)

Ghost Rider III#26 (June, 1992)

Marvels#4 (April, 1994)

Thor I#476 (July, 1994)

Marvel Vision#1 (January, 1996)

Fantastic Four III#538 (August, 2006)