For a long time, Blizzard promoted its games exclusively on its own platform - Battle.net. But times change, and the company announced that it plans to make some of its projects available on Steam. It has not yet been announced what games these will be, it is only known that the first will be Overwatch 2, which is coming there on August 10 (the game already has its own page where it can be added to Favorites).
This is the first appearance of Blizzard games outside of Battle.net (aside from a few classic projects available at GOG). The company explains this decision as follows: "as we’ve evolved, the industry has evolved too – gaming is no longer just for specific communities as it was when Battle.net launched over two decades ago, gaming is for everyone."
Overwatch 2, according to the company, is the perfect "debut" game to appear on Steam - it is a free-to-play game that can quickly attract the maximum number of players on the new platform. And to help it with this, Blizzard decided to release it on the day of the release of the Overwatch 2: Invasion add-on, which will add a lot of new content to the game (new PvP modes, story missions, cooperative events, etc.).
Regarding the future of Battle.net - Blizzard also notes that it is not going to abandon its own platform and will continue to develop and support it.