Elliott Delgado is a reporter. Leah Berglund is an assassin.
That is how they are at the start of the two-book series which takes place in the very near future. Delgado stays a reporter but then acts as a freelance agent for the President in the second book. Berglund is an assassin for a governmental bureau in the first book but quits and then is pulled back as a freelancer by the President. This means that both act as freelance but neither want to be and neither earn a living as such.
Delgado is an acclaimed journalist having won a Pulitzer. He is also a former FBI agent decorated and well-respected by his former colleagues. He had been an agent for over a decade when he was severely wounded in a shoot-out and had to retire on disability. Not wanting to sit and do nothing, he changed careers and used his investigative talents in a different way. This resulted in numerous high-profile exposes, the best being the facts on a secret government department's misconduct.
Berglund is an agent with the Bureau of Illegal Substance Control (BISC). This department, a merger of the DEA and the ATF, came about when the drug cartels launched an incredible series of attacks on the justice system around the country hoping to cripple it for years to increase their profits. Instead, it created a backlash of sentiment that 'demanded' something be done and that something was an extra-legal department with the power to investigate, judge, and then punish as needed. As a field agent, it is Berglund's job to take a case handed her, check out the facts as they were alledged and if finding them credible, be prepared for an elimination order. She does not like the killing she is tasked with doing but she dislikes the drug dealers even more for personal reasons.
In the first book Delgado is falsely accused of being in cahoots with the drug purveyors and Berglund is given the job of looking into him and probably removing him. In the second book, they are asked by the new President to look into something far different.