The new Tomb Raider will feature the first ever multiplayer experience in the history of the series. The re-imagination for Tomb Raider was originally focused on the single player experience, but after looking at Guardians of Light, the development team realized they needed multiplayer.
Eidos Montreal is leading up the multiplayer development. Lara Croft won't be alone. The focus is on the group surviving together and the traversal of levels. The environment can be a threat to players, so look out for explosive ammo boxes and other traps.
Have a look at the video below--the fourth Final Hours of Tomb Raider diary. There are two more left in the series. The game is out March 5.