If you want to play some co-op online, you'll have to wait.
Capcom has confirmed that online play for the Raid Mode in Resident Evil: Revelations 2 has been delayed. It will now be available "shortly after" the final episode launches in March.
They want to make sure the co-op "will function as expected," so they need some extra time. However, you can always enjoy solo play and split-screen co-op in the meantime; it's not like Raid is unplayable. You just can't team up with someone online. Raid Mode offers 15 total playable characters and more than "four times" the available skills, so it's definitely a big portion of the game.
The first episode for Resident Evil: Revelations 2 will be ready to go on consoles and PC on February 24.
Related Game(s): Resident Evil: Revelations 2