Expedition is the first DLC coming to Titanfall and it consists of three new maps.
Swampland is a forest themed map with tall trees to run and jump off of. It looks like it has a lot of good sniping areas as well. Runoff is a cityscape map with three levels to fight in with large open areas as well. Finally, Wargames is a futuristic simulation style map with long routes and corridors.
The DLC comes out in May for the PC and Xbox One and in June for the Xbox 360.