The first Blizzard game coming to Steam will be Overwatch 2, and it’ll be available on August 10th — just in time for Steamers (that’s what they’re called, right?) to participate in the Overwatch 2: Invasion event that introduces the long-awaited PvE story missions.
I’d say it’s more a continuation of how Activision put COD back on steam when they tried to keep it on their platform for a few releases.