Odyssey added another way to gain combat experience. On-foot combat resulted in a better way to gain Combat rank. Since the introduction of the Mercenary rank, hunting down NPCs, in settlements resulted in Combat rank experience, and a small percentage goes to the Mercenary rank. On the other hand, doing ground CZ will get more experience to your Mercenary rank and a small percentage goes to the Combat rank. Odyssey released a patch that had notably "removed the zeroing out of Rank Progression points for Combat and Mercenary Rank when killing an enemy a given number of ranks below you.