At BlizzCon, Blizzard expressed intense interest in SteamOS, and were very pleased with Valve. Previously, they've said they're dissatisfied with the direction of Microsoft, and actively decided to not support the XBox One with Diablo 3: Reaper of Souls. They also announced Hearthstone for Android, and started talking about "getting their games to as many platforms as possible where it makes sense", and by that they mean the control scheme. In the meantime, every single Blizzard game has an internal check for whether it is a Windows, Mac, or Linux client, as many have already pointed out. In addition, they have been expanding their team and hiring Linux engineers for a while now.