Halo: Reach is being added to Halo: The Master Chief Collection and the entire collection is coming to PC via the Microsoft Store and Steam.

 

1) Halo: Reach is being added to Halo: The Master Chief Collection and 2) the entire collection is coming to PC via the Microsoft Store and Steam!

Source: MCC PC & Halo: Reach | Halo: The Master Chief Collection | Halo – Official Site