Glover is seen standing in a forested area next to a white pick-up truck and and a man who might be actor Logan Marshall Green (who is rumored to be playing a villain) who is shooting a bright white light off into the sky with Shocker-type tech leading to a huge electrical explosion.
Based on this super-short scene alone, it doesn't seem like Glover is on the right team here. In fact, it looks like he may be supervising the man who is setting off the explosives, in a boss-type situation.
Glover has an interesting story as to how he got cast in Spider-Man: Homecoming in the first place. Donald voices Miles Morales, a Black Hispanic version of Spider-Man from Marvel's Ultimate universe, on Disney XD's Ultimate Spider-Man.
It all started with a fan asking him on twitter if he would ever play the iconic webslinger when Sony began casting for The Amazing Spider-Man. Glover explains this in his stand-up comedy special Weirdo. Fans loved the idea and Glover "ran with it" and got behind the social media campaign.
He obviously wasn't cast as Spider-Man at all, nor will we be seeing Miles Morales, but he does have a part in Spider-Man: Homecoming.
More Spider-Man: Homecoming: Domestic Trailer / International Trailer / First Look at Shocker / Iron Man Cameo Revealed / SPIDER-MAN HAS WINGS! / Jacob Batalon Reveals Role / Will Liz Allan Be Peter Parker's Love Interest?
Doctor Strange is now in theaters; Guardians of the Galaxy Vol. 2 – May 5, 2017; Spider-Man: Homecoming – July 7, 2017; Thor: Ragnarok – November 3, 2017; Black Panther – February 16, 2018; Avengers: Infinity War – May 4, 2018; Ant-Man and the Wasp – July 6, 2018; and Captain Marvel on March 8, 2019.