There is no way it is coming next year. They would have had 2019 after trailer like Gears 5 or others. Also alot of their interviews have hinted its still very far away. They didnt even show ingame graphics or gameplay.
Halo 5 came out October 2015 so it's almost 3 years since Halo 5. If Halo Infinite drops holiday 2019 that would be 4 years which is more than enough to have the game done. A lot of the game is probably done by now so it's hard for me to see it launching holiday 2020. If the game isn't coming to Xbox One I don't think MS would announce it. Latest I'm expecting it is Q1 2020 but I'm expecting holiday 2019.