Big changes are coming to the Underground DLC in Tom Clancy’s: The Division

Improved loot, Hunter adversaries, new directives, and checkpoints are all included to enhance the player experience in Underground content. Bosses and Hunters will both have a chance to drop exotic gear after the update. Hunters have a chance to spawn in Underground sessions on hard or challenging difficulty. A number of Hunters that spawn is the same as the party size plus one additional mob.