For the first time Pixar is taking on a Marvel property.  Big Hero 6 is a superhero team that–at least in the comics–has ties to Marvel’s X-Men.  In fact, the comic where they first appeared was called “Sunfire & Big Hero 6.”

Sunfire being a mutant from the X-Men comics.

And seeing that connection and the fact that mutants, like Sunfire and the X-Men, are licensed to Twenty-First Century Fox it implies that the contacts are either a bit labyrinthine (or convoluted, depending upon how you look at such things) and you can never be too certain which characters licensees can or cannot use.

And after watching the trailer you can tell that they’re taking a few liberties with the material, though I like what I see because it’s a really amusing trailer.