In the Black universe, the CIA use Black Ops teams. The one that Jack Kellar is in is Bravo team, and, aside from the emotional cutscene at the end of the dockyard level, are the only ones visible. Because two other teams mentioned are Charlie Team and Alpha Team, it is most likely that each squad has a Greek letter in it's name (Delta, Gamma, etc) in it's name. Charlie Team is never seen, but Alpha Team seems to have a large amount of soldiers, as opposed to Bravos 3, meaning it is possible that each team has a random number of operatives, or Bravo Team just took causalities (Which is likely, as in the first level, if you listen carefully to your radio, a soldier will say "I have multiple casualties").