What exactly do we know about it/them?
I was hoping in the lead-up to RE5 that it would be revealed to be Tricell, or what was it, "S?" Regardless, I personally have always been intrigued by this part of the series' canon, but it seems to have been shrouded in mystery more and more each game.
You'd think with how much we've seen of Ada and Wesker we'd know more about it. Was Wesker aligned with them? If so, for how long? Was he with them when he collected BOW combat data from the STARS/Arklay Mansion incident? Was he working for anyone during RE5 or was he completely rogue by then, not aligning himself with any pharmaceutical or BOW organizations? How did Ada factor into this "Organization?"
Maybe we'll learn it's actually been a U.S. government agency this entire time; the same one Simmons is working for or leading in RE6.