The GameSpot product page states, ”Purchase the Aliens: Colonial Marines Season Pass and get access to four downloadable content packages at a 33% discount! All add-on content packs are scheduled to be released from March through to summer 2013. The Aliens: Colonial Marines Season Pass will give you access to campaign content, additional multiplayer maps, new modes, character customization and more!”
Additionally, a GreenMan Gaming product page warns, ”If you purchase this Aliens: Colonial Marines Season Pass, all included content should be downloaded in-game and NOT from Steam, or you will be charged twice. Aliens: Colonial Marines game required (sold separately).”
Aliens: Colonial Marines is due to be released on the 12th February for PC, Xbox 360 and PlayStation 3.