1)The Dark Knight Rises. A terrorist organisation managed to create a nuclear bomb and took over an entire american city for months.
Not only this would probably make the american government and public even more paranoid about the war on terror, but it would also have huge rsmifications regarding the use of nuclear energy.
Of course Batman's mere existence will have some truly weird repercussions on american society
2) The X-Men prequels (First Class-Days Of Future Past-Apocalypse-Dark Phoenix). I fell like the existence of superpowered individuals would significantly alter the course of the Cold War, especially after Apocalypse sent all the nukes of the world in space
3) The Marvel Universe. Tecnology is far more developed than OTL, they have at least two living proofs that nordic gods are real, there are multiple alien races operating on earth and magic is real.
I also wonder how human society was impacted by the events of Infinity War