Spider-Man: Marvel May Have Already Spoiled Zendaya's MCU Return
"Spider-Man: No Way Home" had the unexpected ending of everyone forgetting who Peter Parker (Tom Holland) is, including his love interest MJ (Zendaya). Rather than reintroducing himself to her at the end, he walks away, knowing she's safer away from Spider-Man. It would seem to be the end of the character's time in the Marvel Cinematic Universe, but based on the mythology presented in "Spider-Man: Across the Spider-Verse," she could come back sooner than expected.
"Across the Spider-Verse" establishes the idea of "canon events," with Miguel O'Hara (Oscar Isaac) explaining, "There's moments in our stories that are the same for all of us. Some good, some bad." For Spider-Man, these include losing an uncle or another loved one and having a police captain close to Spider-Man dying. These events must occur, or the fabric of reality could be destroyed. But one canon event is that Peter and MJ will fall in love and get married. Looking at the MCU Spider-Man films, this implies that MJ isn't done with Peter Parker just yet.
Characters in "Across the Spider-Verse" are aware of the existence of the MCU, a.k.a. Earth-199999. Miguel references the events of "No Way Home" in "Across the Spider-Verse," so it would make sense for the MCU to abide by the same rules presented in the animated film. To abide by canon, it would seem as though Zendaya's return to the MCU is a matter of "when," not "if."
Then again, what if Miguel is wrong about canon events?
Outside of the canon event theory, it makes sense for Marvel and Sony to try and get Zendaya in another "Spider-Man" movie. She's one of the most popular actresses working right now, and she's a major draw for all of the MCU "Spider-Man" films so far. She wouldn't even necessarily have to come back right away. Peter Parker could have a romance with Gwen Stacy in "Spider-Man 4" before MJ comes back in "Spider-Man 5" or something. But even if Zendaya is too busy to reprise the character, there may be a permanent out after all.
Miguel O'Hara is adamant Miles Morales (Shameik Moore) follow these canon events so that his reality doesn't collapse. That means allowing Miles' father, the new police captain, to die. Miles tries to stop this, and we'll see if he succeeds in "Beyond the Spider-Verse." If Miles manages to keep his dad alive while protecting the state of his universe, it could show how canon events aren't as strict as Miguel thought. In the event Miles can show how Spider-People don't always have to follow the same script without consequence, it could open the doors for more intriguing Spider-Man stories down the line.
It may even make it easier for audiences to accept that Zendaya's MJ isn't coming back to the MCU. If a wedding to MJ doesn't have to be canon, it would allow Tom Holland's version of the character to move toward other storylines that don't involve her. Right now, anything is possible, and there's no confirmation on whether MJ is even a part of "Spider-Man 4." But with a multiverse of possibilities, she may remember her high school love pretty soon.