Each playlist within Halo: The Master Chief Collection uses an independent skill-based ranking system that is identical to the leveling system from the original Halo 2. The system uses the same exact XP requirements as the original Halo 2; players will earn XP when they win and lose XP when they lose, and total XP will determine their rank. You will have a skill-based ranking per each playlist; we ultimately decided not to have a 'master' ranking across all four games combined, given that player skill and approach varies radically between game chapters.
Additionally, we’ve also modified matchmaking to use skill detection, which will put players into the fairest matches faster than any Halo game to date. In ranked hoppers, players will be evaluated after each match and can go up or down in ranks depending on how well they perform.