I just realized that halo 6 might be like a halo CE the same things have so far happened something threatens the planet that the infiniti/pillar of autumn ship is on and that ship excapes to an unknown sector soon realizing they have just found an unknown installation or forerunner artifacts which is being protected by the enemy.
We all know that Cortana and many AIs are the new enemy. And she will be using Prometheans, im wondering since she used the Guardians, that her and the other AIs can control ships and built a fleet. Chief, Locke, and Arbiter will be on Halo 6, Dr. Halsey may have something she made to either destroy Cortana of fix her. And when you beat Halo 5 on Legendary, there’s a extra clip on the ending showing a new Halo ring.