system
Given the following post, respond as if you're commenting on Reddit:
human
[DC/Marvel] Let's say the Kansas of the Marvel Universe was where Superman landed as a child and was raised similarly by that reality's version of the Kents so he establishes the same ethics and connection to humanity. How would this world react to having Superman in it?
gpt
For starters, Captain America and Superman are fast friends. They form a quick bond, akin to his friendship with Batman.

People of his power level aren't unheard of in Marvel (Thor, The Sentry, Hyperion, etc.), so he doesn't change the superhero game too much. Ultimately, Marvel's heroes just became more effective by the measure of one Superman. The public sees him similar to how they view Cap, usually on his side but capable of being turned against him. He joins the Avengers at some point, likely as a founding member (maybe one of the times they broke up then reformed). Clark can always be found where he's needed.

I haven't read many major Marvel events, but I'll comment on Superman during Civil War. Clark starts off on Tony's side, due to the destruction of the school. As time goes by, he grows more and more worried with the brewing conflict and Tony's increasingly desperate responses. Eventually, Clark defects and chooses to focus on minimizing damage and not picking sides. The absolute latest this could happen is the death of Goliath. If Superman is there when Bill dies, he takes the Thor clone down hard.