Put simply, Peter has been allowed to grow up. Miles Morales, meanwhile, fills the role of high school hero just beginning his journey as the all new Spider-Man. By and large, the plot of this revised Homecoming film follows two major plotlines. An added origin for Miles Morales, and Peter's attempt and mentoring the young hero fighting the criminal Vulture.
The corporation which incurs Adrian Toomes's wrath isn't Stark Industries, but rather the newly introduced Alchemax, a company which rose from the ruins of Oscorp, following the deaths of both Norman and Harry Osborn years back. Head of the company is a scientist who once worked under both Osborns; a geneticist by the name of Miles Warren.
Miles is less eager to become one of the Avengers, like Peter Parker did. Miles's origin covers the first act of the movie, starting with an unseen thief stealing several genetically-engineered spiders from Alchemax. The project is hinted at being an attempt by the company to create their own Spider-Men, or at least replicate his power.
