With last year's Call of Duty: Black Ops 3, Treyarch added to their create-a-class sytem by introducing "Specialists", where players can choose from nine different character types that each have unique abilities/weapons. With 2016's Call of Duty: Infinite Warfare, developer Infinity Ward refines that by straight up feature six classes.
Call of Duty: Infinite Warfare's multiplayer class-based system dubbed "Combat Rigs." Think of these as the suits and combat gear of the future, and there are six to choose from and each offers a customizable combat suite. You can customize and swap mid-match.