Halo: The Master Chief Collection Ranks Explained

"343 Studios has revealed that each playlist in Halo: The Master Chief Collection will use a skill-based ranking system identical to the leveling system from Halo 2. If you never played Halo 2 then you’ll be in for a treat as this ranking system is totally different from the one adopted by Call of Duty. To put it simply, when you win a game you gain experience, however losing a game will result in experience being taken away." – GeekFed.com