Seems State of Decay 2 might be coming to Steam and not just the Windows Store.
The PAX East Demo seems to "imply" that it connects to Steam servers:
*in case picture is removed by host, it features State of decay 2 - played at Pax and shows a "login failed" alert, that says "unable to connect to steam, Make sure steam is running, your logged in... bla bla bla".
Necro-bump this 2020: http://gamrconnect.vgchartz.com/thread.php?id=229249
Bumb in 2021: http://gamrconnect.vgchartz.com/post.php?id=9047071