With the release of a new Spider-Man movie -- and one that's premiered to critical and audience acclaim -- there's the question of if and how Spider-Man: Across the Spider-Verse fits into the larger Marvel Cinematic Universe.
In short, the second in the planned trilogy of animated Spider-Man films is not part of the MCU. But, the new movie is full of references to the Disney-owned MCU and its beloved superheroes.
The Spider-Verse movies (Into and the Spider-Verse and Across the Spider-Verse) are owned by Sony, which legally owns the rights to the character, his villains and other Spider-Man adjacent characters and stories. Sony bought the rights to Spider-Man in the 1990s, and since then has cranked out several iterations of the character with Tobey Maguire, Andrew Garfield and Tom Holland playing the web-slinger in live action.
Shameik Moore voices Miles Morales as Spider-Man in the Spider-Verse movies, with Hailee Steinfeld as Gwen Stacy, Jake Johnson as Peter B. Parker, Oscar Isaac as Spider-Man 2099/Miguel O'Hara and more voicing carious Spider-persons.
The new movie is full of Easter eggs, including some nods to the characters and events of the MCU.
In the beginning of the movie, Miguel, Gwen and Jessica Drew/Spider-Woman take down the papery Renaissance version of Vulture. Miguel comments about how he hates "incursions" like this and the one with "Doctor Strange and the little nerd from Earth-199999."
This comment is a reference to Spider-Man: No Way Home and the multiversal collisions that happened after everyone learned that Spider-Man (Holland) was Peter Parker. In that movie, those incursions are Maguire's and Garfield's Spider-Mans as well as villains Green Goblin (Willem Dafoe), Doc Ock (Alfred Molina), Electro (Jaime Foxx) and Lizard (Rhys Ifans).
Donald Glover's character from Spider-Man: Homecoming also makes a cameo appearance. Glover played Aaron Davis, Miles' uncle, in the MCU movie and appeared in Across the Spider-Verse as the Prowler after being caught as an incursion.
There are also moments that show scenes from the live-action Spider-Man movies starring Maguire and Garfield, whose appearances in No Way Home made them a part of the MCU -- just in different universes.
With multiverse stories and characters appearing in both Disney's MCU timeline and Sony's, the discussion of being part of one continuity or canon or another becomes nearly irrelevant. And it's not surprising, as comic book stories have done similar things for decades with the creation of different Earths in different universes and hundreds of different Spider-persons.