"We expect Microsoft to abide by its contractual obligations and ensure that Activision's games are multi-platform." A Sony spokesman told the Wall Street Journal. This is the first and only reaction so far from Sony to the announcement of Microsoft's takeover of Activision Blizzard.
It is not known to the public what contractual obligations Activision has towards Sony or PlayStation. However, it is a known fact that PlayStation has been a partner platform for Activision's biggest series for years - Call of Duty. Players on the PlayStation are thus the first to get a chance to test new Call of Duty games, and some mods are temporarily exclusive to them.
Such partnerships are usually negotiated for a longer period, so this may be exactly what will keep Call of Duty on the PlayStation for at least some time. Microsoft has previously shown fairness to the contractual obligations of the studies they have undertaken. Although Bethesda’s studios are now owned by them, their Deathloop and Ghostwire Tokyo games are still temporary exclusives for the PlayStation platform, as previously agreed.
Microsoft has said it has no intention of destroying existing Activision Blizzard gaming communities, so older games are expected to remain on the PlayStation for sure.