Aside from its relative success on the Windows 10 UWP platform, Killer Instinct official Twitter account today confirmed that the game and all its content will be released on Steam this year. This means that the game will no longer be exclusive to the Windows 10 Store, so Windows 7 or 8 users can also enjoy it via Valve’s digital distribution platform.
Killer Instinct Will Be No Longer Exclusives To Windows 10 Store
That's right, KI is coming to Steam later this year! Thanks to @CEOJebailey for helping us break the news. More details to follow.
— Killer Instinct (@KillerInstinct) June 17, 2017
Like the Steam version of Halo Wars: Definitive Edition, it is logical to assume that there will be no cross-play with users of Xbox One, nor with those of the UWP platform of Windows 10.
Hopefully more exclusive titles of the Windows 10 Store, such as Gears of War 4 and Forza Horizon 3, among others, sooner or later also come to Steam.