Context: American cheese, Cheez Whiz, and provolone are the most commonly used cheeses or cheese products put on to the Philly cheesesteak.

Question: what kind of cheese for a philly cheesesteak?
Steam of consciousness below:
To answer this question, we should know that: American cheese, Cheez Whiz, and provolone are the most commonly used cheeses or cheese products put on to the Philly cheesesteak.
So, the answer is American cheese , Cheez Whiz , and provolone.