The Overrun DLC contains:

4 new PvP maps - Enjoy various locations in PvP matches with these new maps.

A new PvP mode – In Overrun, three different locations must be captured in each map. As only one location becomes active at a time, both teams have to fight for control of these neutral locations to protect them from being overrun by their opponents.
To ensure victory, you willl have to use all resources available and develop new strategies...

A new vehicle - The Buggy is now available in the PvP battlefield.