The Halo 3 spin-off ODST will be released on Xbox One on May 29th.
The game will join the Master Chief Collection, which also includes Halo 1, 2, 3 and 4.
ODST was announced late last year as compensation for gamers that suffered from the Master Chief Collection's troubled launch (available to anyone that bought the game between launch and December 19th). But there's no news as to whether it will be made available to those that bought the game after this time.
The Master Chief Collection now includes all first person Halo games with the exception of Halo: Reach.