This means they now own Bethesda Softworks, Bethesda Game Studios, id Software, ZeniMax Online Studios, Arkane, MachineGames, Tango Gameworks, Alpha Dog, and Roundhouse Studios.
This gives Microsoft a huge swath of exclusives going forward. While they've said they're excited to bring these games to Xbox and PC, they haven't specifically said that new games from these studios won't come to PS5, but it's very doubtful they'd pay $7.5 billion and keep making games for their competitors. While they're now ironically publishing a few timed Sony exclusives, it's a fairly safe assumption that when the Elder Scrolls 6 finally releases, for example, it'll be Xbox and PC exclusive. In, y'know, 2035.
I really only want to play most of the games that this acquisition affects on PC, so this isn't a huge hit for me, but this definitely cuts into the argument that Sony has the best exclusives. Right now, they definitely do, but give it a couple years and things will change.
What's most surprising about all of this honestly, is that it didn't leak. Nobody was talking about this at all.