Sony shouldn't be impacted by the Activision Blizzard acquisition this console generation, and depending on the marketing deals, Call of Duty might not even be on GamePass until a few years from now at the very least.
The question that remains is whether or not that period is enough time for Sony to prepare against the possibility (or shall I say inevitably) that Call of Duty is taken off PlayStation platforms. I've voiced this many times on this forum, but I believe that is entirely possible, if Sony is willing to spend 10B - 20B+ for their gaming division. While Sony can't outspend Microsoft, they can still make major strategic acquisitions that strengthen their platform and content library, to the point where if Microsoft were to pull Call of Duty permanently, they could damage its popularity (although it would still be one of the most popular games).
That's before variables like Sony's transmedia push, which could further elevate the likes of popular games like Gran Turismo, Destiny & Ghost of Tsushima, or the potential that one of their multiplayer projects hits big. For as much weight as Call of Duty holds, that didn't stop the likes of Fortnite, Destiny, Apex Legends, Rocket League, PubG, Genshin Impact, etc, from being insanely successful.