A new trailer for Halo Wars 2 has been released, in addition to a number of details about the upcoming game. The game will launch on February 21st, 2017, for Xbox One and Windows PC. In addition to this, an open beta is available right now on Xbox One and will last for a week until June 20th. A new faction is also being added to the game in the form of The Banished, with a new enemy leader known as Atreox. The game will be Play Anywhere enabled, meaning it can be bought on either Xbox One or Windows 10 and played on both.
Source: Microsoft E3 2016 Showcase