Unlike the latest titles coming out on Xbox One, like the Master Chief Collection, Halo 5: Guardians will not enjoy any kind of graphic optimization with the transition to Next-Gen.

The news was confirmed by Microsoftsame:

“While Halo 5 will not have the same optimization on the Xbox Series X and Series S as on the MCC, owners of next-gen consoles will still enjoy the hardware benefits, such as faster load times and higher resolution. "

No Cortana in 4k / 120 fps, but Halo 5 players will still be able to finish the campaign much faster.