There are many great Marvel legacy heroes who should turn up in the MCU at some point, but Miles Morales finds himself right at the top of the list because a) he's a popular character who deserves a shot at live-action and b) his arrival has already been teased.
In Spider-Man: Homecoming, Donald Glover - who has voiced Miles in the Ultimate Spider-Man animated series - played Aaron Davis, Miles' uncle in the comics. He even mentioned his nephew in the movie. If you want more proof, Kevin Feige himself said this was deliberately done to plant seeds for a potential role for Miles further down the line.
There would be a couple of issues with bringing Miles into the MCU, of course. One is that he wouldn't be replacing Peter as Spider-Man like in the comics. Instead they could just make him an adjacent Spider-Man. Marvel Studios have played with so many core elements of Peter's character that giving him a partner wouldn't seem all that shocking.
The bigger problem would be that Sony might not allow it. After all, they already have their own animated movie starring Miles in the works, so they might not want to share the character.
If the studio can find a way to organically insert Miles into the MCU, though, they need to do it and bring one of the most successful new additions to the Marvel universe in recent years onto the screen.
Which Marvel legacy heroes do you want to see join the MCU in Phase Four? Let us know in the comments!