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