Halo Wars: Definitive Edition will be available on Steam come 20 April. And no it's not a 4/20 joke. The remastered edition will cost around £15 and cross-play with the Windows Store versions will not be supported.
Halo Wars: Definitive Edition is an enhanced version of the Xbox 360 real time strategy from 2009, and its getting a standalone PC release really soon. I say "standalone" because the game was already released for PC in late 2016, but only as a bundle with the "Ultimate Edition" of Halo Wars 2.Steam
The price is said to be in the neighbourhood of £15, so the people who bought the Ultimate Edition of Halo Wars 2 didn't save money, but they did get a four month early access kind of a deal. And that is something. The Definitive Edition was previously available as a part of a £63 bundle.
The original Halo Wars was released in 2009, and it was the first real-time strategy of the Halo franchise.