Seriously. Before you say, “Well, it can’t be done, cuz it’s not feasible” there are many games on Xbox right now that support it. Why can’t Halo?
Halo supports it on PC, however I’m not sure why they can’t patch it in but that might be a reason why…
You can change up your button layout in the xbox controller setting area. That might be one way of changing the controls in Halo 5.