The pre-fight dialogue between Iron Man and Captain America is taken from their fight in the "Civil War" storyline in the comics where they were on opposite sides of the government's choice to register superheroes.
Deadpool using the Shoryuken, a signature move from the Street Fighter games, comes from an incident in the comics where he used it to knock out Kitty Pryde to goad Wolverine into fighting him.
This is the second Marvel vs. Capcom game where Resident Evil Characters are playable, Marvel vs. Capcom 2: New Age of Heroes (2000) features Jill Valentine as a playable character.
This video game takes place in the Earth-30847 of the Marvel Comics multiverse, together with The Punisher (1993), X-Men: Children of the Atom (1994), X-Men: Mutant Apocalypse (1994), Marvel Super Heroes (1995), Marvel Super Heroes in War of the Gems (1996), X-Men vs. Street Fighter (1996), Marvel Super Heroes vs. Street Fighter (1997), Marvel vs. Capcom: Clash of Super Heroes (1998), Marvel vs. Capcom 2: New Age of Heroes (2000), Ultimate Marvel vs. Capcom 3 (2011) and Marvel vs. Capcom: Infinite (2017).