The Suicide Squad is a group of five agents for the CIA.
Carter Stephens, Reece McNair, Brian Godfrey, Amir Farajian, and Kristen Hayes were all good friends who met during training at the Farm and then stayed close for the next few years. Stationed together in Iraq, they come together when Reece is kidnapped along with another woman teaching Iraqi police. They would countermand orders, break a few regulations, and generally cause a good stink in their efforts to free her and they were successful. They were also in deep, deep trouble.
Then they were approached by the Director of the Agency's counter-intelligence division and offered a chance to stay with the CIA and they took it. But that division of the organization was considered an advancement-ender and that meant for these five, working there was tantamount to career suicide, hence the name.