Steve Black is a private contractor.
I could have easily written that he was an agent with the CIA. He and his people are as good as, except for the whole accountability part. In that matter, he is the leader of a small private group of paramilitary operatives working for themselves but contracted to the CIA under the control fo Dean Walker, CIA Special Ops Director. That way, if things went wrong and the actions of the group discovered, the Agency, and by extension, the Administration, could disavow any knowledge and get off with just minor egg on their faces. The team would be left high and dry and likely dead but they knew that going into each assignment so no surprise there.
Black and his team is the group that is trusted by and requested by the President when things get really dicey. They know and trust each other. This works both well and poorly for the team. Well because what they need to get the job done is almost certainly going to be provided when asked for, usually without question. Poorly because having accomplished the near impossible in the past, when it is an extremely nasty suicidal style mission that absolutely has to be done,, the President calls on Black.
His team consists of himself and three others, two male and one female.
Jackson Leonard is the team's quartermaster responsible for getting and keeping the team supplied, sometimes by borrowing from the enemy.
Marcel Jeveaux is the communications and explosives expert, an odd combination because electronics do not function well around things that blow up. He makes it work.
Jean McKenzie is the silent and deadly assassin on the team. If someone is needed killing quietly and quickly and totally cold-bloodedly, she is the best option.