The Commander Jerome Leader Add-on for Halo Wars 2 has 3 achievements worth 30 gamerscore.
Win 3 matches as Commander Jerome (Multiplayer, Skirmish, or Blitz)
Kill 25 units with Jerome's Command Mantis unit. (Multiplayer, Skirmish, or Blitz)
Hijack 40 vehicles with Omega Team members (Multiplayer, Skirmish, or Blitz)