Gunmetal Gray by Mark Greaney
Take a look at this recent run of badass protagonists:
Evan Smoak, an off-the-books assassin, novel #2, The Nowhere Man
Sean Dillon, former IRA assassin in book #22, The Midnight Bell
Jericho Quinn, Special Agent, book #7, Field of Fire
Pike Logan, an off-the-record Taskforce member, book #11, Ring of Fire
And now comes Court Gentry, the Gray Man, the world’s deadliest assassin who returns in Marc Greaney’s 6th novel, Gunmetal Gray.
After five years on the run Court Gentry is back on the inside at the CIA. An old friend is being held hostage by the Chinese who want him dead to make sure he doesn’t find a former member of an ultra-secret computer warfare unit. Court needs to both save his friend and find this Chinese computer operator before they find him.
This is a great series, and as always, I recommend you start with the first book, aptly titled, The Gray Man.