Halo has announced that Halo 2 and Halo 2 Anniversary will be releasing for PC as a part of the Master Chief Collection on Tuesday, May 12th.
Earth will never be the same.
— Halo (@Halo) May 5, 2020
Like the other titles release on PC so far, Halo 2 will be available for purchase on Steam or through the Microsoft Store. You can buy the entire Master Chief Collection for $39.99, which includes every title, or you can buy Halo 2 separately for $9.99.