The Title Update 4.5: Mercenaries Title update for World of Tanks has 8 achievements worth 180 gamerscore.
Complete The Heist War Story successfully
Complete the first stage of a mercenary contract
Complete a mercenary contract
Win 5 Multiplayer battles in a platoon of only mercenary tanks
Win 100 Multiplayer battles in mercenary tanks
Earn a Mastery Badge of Class I or higher on a mercenary tank
Earn Marks of Excellence on a tier V or higher mercenary tank
Destroy 50 enemies in Multiplayer with a mercenary tank