Keep trying spidey

No

if it's a serious question, it's who owns the rights to make the movies, both are at different studios

The avengers are marvel characters and Spider-Man's part of DC So unless they worked together or something spidermans not gonna be allowed in the movie because of copy right laws or something like that

Spiderman is Marvel as well, but owned by Sony Studios, Marvel is attempting to get the rights back to all their characters under one studio so they can make the movies they want. Superman, Batman, Green Lantern, Flash, all these are DC.