Halo 5: Guardians

Halo 5: Guardians is an upcoming Halo game announced during Microsoft's E3 2013 presentation as the second chapter in the John-117 storyline of the Reclaimer Saga and the sequel to Halo 4.

Xbox One Reveal
Halo (Xbox One) was confirmed to be in development for the Xbox One during the Xbox One Reveal event on May 21, 2013.

E3 2013
"There was no ambiguity in not putting a number after the game. For me, what we showed wasn’t the game. Nobody should be confused on that. I didn’t really want to try to show something that was clearly a thought piece by the studio around where Master Chief is in his journey, and then drop the name after it and be somewhat disingenuous about that being the game. But I did want Bonnie [Ross] to come out and say 'First-person shooter. Master Chief.' Because they'll get the questions: 'Hey, is this ODST? What are you guys doing?' Bonnie [Ross] comes out and reaffirms that 343 is building this game. It’s Master Chief. It’s a first-person shooter at 60 frames per second. It’s coming in 2014."

- Phil Spencer, regarding the teaser trailer

Xbox Wire
On May 16, 2014, Bonnie Ross, General Manager of 343 Industries, announced on Xbox Wire that the Halo game will be named Halo 5: Guardians and will be released in Fall 2015. Bonnie also announced that Halo 5: Guardians will run on a new and more powerful engine.

Trivia

 * According to Microsoft Studios' Phil Spencer, "while we originally said 'trilogy,' we've actually expanded this to more of a saga, so we don't want to limit the Reclaimer story within a trilogy."
 * This will be the first main Halo game to be released on the Xbox One.
 * The Halo 5: Guardians multiplayer beta will be accessible through Halo: The Master Chief Collection.
 * Exclusive content unlocked in Halo: The Master Chief Collection will carry over to Halo 5: Guardians.
 * The "new Spartan abilities" mentioned in the Halo 5: Guardians multiplayer beta announcement trailer are not Armor Abilities.
 * Armor Abilities will not be present in Halo 5: Guardians.
 * Jameson Locke will be a playable character in Halo 5: Guardians.