Since 343i took over Halo their has been a release every year. I believe this trend is going to continue.
What I believe the halo line up will be.
2015: Halo 5
2016: Halo Wars 2
2017: Halo 3 Anniversary
2018: Halo 6
2019: Halo ODST Anniversary
2020: Halo Reach Anniversary
2021: Halo CE Remake
Now I have no evidence to support this it is all speculation. I’m sure there will be another halo mobile game release In 2017(The first was released in 2013 and the 2nd one was this year.) but I don’t really care about the mobile halo games they are just cash grabs. From what I’ve been seeing in console news it is possible we could see and new Xbox releasing around 2017-2021. The Xbone will not have as long as a life span as the 360 and it may get cut shorter because of the new Nintendo coming out.
What I believe each halo will be.
2015&2016: I’m not going to talk about H5 or HW2.
2017: Halo 3a, What I hope it will be is a stand alone release with a remastered campaign, matchmaking, forge, and customs. If 343 didn’t learn from their mistakes it could just be a map pack for halo 5 like with Halo CEA. A lot of people think it will be a DLC for Halo MCC but that won’t happen 343 wouldn’t make enough money off of it because the pop is so low. Besides MCC is still half the game it should have been do you really wanna see them adding another barely working game to it?
Something else we could see is it could release along side Halo Online or Halo Online could be H3A… But I would like to see both a PC and Xbox release.
2018: Halo 6 (If you don’t know it was conformed back when halo 4 was.) Depending on how well halo 5 does halo 6 could be as halo 3 was to halo 2 or if halo 5 does bad it could go back to the classic way of playing. Who knows. Also It could be a Launch title if Microsoft deside to end the Xbones life span early.
2019: Halo ODSTa could be the last time we see Firefight In a halo game.
2020: Halo Reacha it could be a stand alone with Remastered campaign, matchmaking, forge, and customs. or a map pack for halo 6.
2021: Halo CE Remake. I really believe halo CE should get remade with a new engine not just remastered. I think thats what we were all hoping for in 2011… It could have all the old maps remade along with the campaign and have a forge mode, Matchmaking, and custom games. I think Playing the old halo maps with Spartan abilitys would be fun…