Michael Keaton played Adrian Toomes/The Vulture in Spider-Man: Homecoming, and by the time all was said and done, the villain had been defeated by the wall-crawler and placed behind bars.
In the first trailer for Morbius, Toomes was shown wearing a prison jumpsuit and speaking to the title character. Seeing as the MCU and SPUMC are different worlds, fans were left confused, especially when a shot of Spidey elsewhere in the teaser showed the hero decked out in the suit from Sam Raimi's movies.
It feels like there's something Multiverse-related going on here (especially after Loki), and that might have been confirmed by Keaton's confusion upon his role in Morbius being explained to him.
The Hollywood Reporter explains that the filmmakers "started talking him through the logic of the fictional universe" by "referencing recent Marvel plot points," but that's where they lost him. "I’m nodding like I know what the [frick] they’re talking about. I go, ‘Uh-huh.’ And I’m thinking, ‘You may as well be explaining quantum physics right now to me,'" he explains. "'All I know is I just know my guy. And I know the basics.'"
"So finally, they were looking at me, and they just started laughing. They said, ‘You don’t know what we’re talking about, do you?’ I said, ‘No, I don’t, no idea what you’re talking about.’"
Ever since Sony Pictures struck a new deal with Disney, we've heard that Spidey is going to start swinging between worlds. With Spider-Man: No Way Home clearly set to dive headfirst into the Multiverse, the reason for another Toomes being in the SPUMC could soon become clear...unless the likes of Morbius and Venom are about to become canon in the MCU!
As for Keaton, he didn't really keep track of comic book movies after starring in Tim Burton's Batman films, but is well aware of their importance in Hollywood today. "They’ll be doing Marvel movies forever. I’ll be dead, and they’ll still be doing Marvel movies."