This summer, there are three Marvel movies coming out (Captain America: The Winter Soldier, X-Men: Days of Future Past, and The Amazing Spider-Man 2) but due to a complicated web of licenses and rights, these movies don’t exist in the same world.
To understand the role of the three studios (Marvel, Fox, and Sony) and what properties each studio controls, I’ve made a video outlining these franchises.
Hopefully this helps!