List of Halo 5: Guardians commendations
From Halopedia, the Halo wiki
Every commendation, save for Mastery commendations, has five tiers. Completing a commendation (and in some cases, advancing tiers) awards REQ packs and XP. Compared to earlier games, commendations in Halo 5: Guardians feature much lower totals and as such are much more easily completed. Unlike previous games, commendation tiers do not have names.
Enemy commendations are awarded in Warzone only.
Marine Replicant Slayer
Kill Marine Replicants
Game Mode Masteries
Spartan Company Commendations
The Spartan Company Commendations are a set of Commendations for Halo 5: Guardians, which can only be gotten if the player is in a Spartan Company. The Kill Commendations are used to unlock ACHILLES-class Mjolnir in the game.
Game Mode (Spartan Company)
Game Mode Commendations