Undead Labs/Microsoft Game Studios
After Microsoft announced back in May plans of bringing its games to rival digital storefronts, State of Decay 2 will be joining Gears 5 and Halo: The Master Chief Collection on Steam. According to the game's Steam page, it'll get an early 2020 release. Undead Labs said the Steam version would support cross-platform play with the Xbox Live, similar to the version on the Microsoft Store for Windows 10.
Source: Polygon