The drone would have had its own progression system and skills to choose from and could have acted in either an offensive or defensive role.
As shown in the E3 2015 trailer, the drone would have been controlled by a player using a tablet. Ultimately, both the drone and The Division tablet app were cancelled due to concerns of imbalance.
As of the Incursions update, drones are used by the Last Man Battalion during Falcon Lost, along with being apart of certain waves on Resistance. They have fairly weak armor and very low health, making them easy to dispatch if the player has on-par gear. They also come in two variants: One fires normal bullets and is identified by a red targeting laser, while the other fires shock darts similar to the Turret's Zapper Mod, and is identified by a blue targeting laser.