WARNING: The following article contains spoilers for Avengers: Endgame, in theaters now.
The new trailer for Spider-Man: Far From Home has got everyone talking about about the Multiverse. Whether or not Mysterio is telling the truth about having traveled between universes in The Snap, if Nick Fury is taking Mysterio's claims seriously, then audiences have reason to believe Multiverse crossovers are a possibility for the MCU. In particular, people are speculating about other Spider-people entering the MCU... particularly Miles Morales.
It makes sense for people to assume Miles could be a Multiverse crossover character. After all, his whole presence in the 616 comics universe is due to such an inter-dimensional jump, and the Miles-centered animated film Spider-Man: Into the Spider-Verse popularized Multiverse storytelling for mass audiences. However, the groundwork for Miles' MCU debut to happen sooner than expected has already been set, and it doesn't involve any alternate universes.
We know there's a Miles Morales living in the MCU. Donald Glover played Miles' uncle Aaron Davis, aka Prowler, in Spider-Man: Homecoming, and he directly mentioned his nephew. From that hint, it's been assumed Miles becoming Spider-Man in the MCU was at least a possibility, even if it was in the distant future. After Avengers: Endgame, though, that future is much closer than it once was.
The big reason Miles seemed like a distant prospect was that Miles has always been written as a character who looks up to Spider-Man before becoming Spider-Man. You need a well-established Peter Parker Spider-Man to tell a recognizable version of Miles' story. From the audience's perspective, however, Tom Holland's Peter Parker is still a relatively fresh face, introduced only three years ago in Captain America: Civil War and only having one film of his own thus far.
But after Endgame's five year time skip, the in-universe perspective of the characters is different from the audience's. Even if Peter Parker has only really been in action as Spider-Man for two or three years, his legend has now had seven or eight years to grow. The friendly neighborhood superhero who went to space to fight Thanos, lost for years but truimphantly returning, the protege of the man who sacrificed himself to save the whole universe: it's the stuff legends are made of.
Let's say that MCU's Miles Morales was five years old when Peter became Spider-Man, and then survived The Snap. He'd be 12 at the time of Far From Home. If Sony and Marvel keep on a two year schedule for Spider-Man films, Miles will be 14 in time for a third MCU Spider-Man movie, the perfect age for him to start developing his own spider powers.
Miles would have grown up with the legend of Spider-Man. Even if he's closer in age to Peter Parker than typical depictions, he's still had enough time to look up to him to allow for an interesting but still recognizable variation on the character. Given how popular Miles Morales has become after Into the Spider-Verse, Marvel would be crazy not to take advantage of Endgame's no-Multiverse-necessary groundwork for introducing Miles in the next few years.
Though if we're doing Multiverse stuff and the animated Miles meets live-action Tom Holland in Into the Spider-Verse 2, that's cool too.