Rima Alaily, the corporate vice president of Microsoft's Competition Law Group, has stated that removing Call of Duty from PlayStation in the future (if Microsoft would end up buying Activision Blizzard) would be a poor business decision. While speaking to Axios about this, she said "It makes zero business sense to take Call of Duty off of PlayStation"
Alaily went on to explain that the Call of Duty franchise has a large player base on PlayStation, and it would not make sense to exclude them from the game. The reason is that cross-platform play and cross-progression have become increasingly popular, which means that limiting the game to just one platform would not be beneficial for the game's overall success.
Alaily's comments suggest that Microsoft is focused on rather expanding the player base and ensuring that the game is available to as many people as possible, regardless of which platform they choose to play on.