Billy Summers by Stephen King (2021) Scribner

Billy is a hitman - has been since he returned from Iraq.  He wants to retire, but there is one last job to do, it's to hit a hitman who got too visible and killed someone he shouldn't have.  The client wants Billy to follow a specific escape plan.  Billy does the job, but he does his own escape, which is a problem for the client.  While hiding in the same town as the hit, he sees a van stop and toss a body across the street.  He checks and it's a girl who has been drugged and raped.  He hauls her into his hideout and cleans her up.  When she comes to, she thinks at first that he hurt her.  But as her memory returns, she gets mad at her 'boyfriend' and his buddies.  When it's time to go on the run, she goes with Billy.  There is still one more job to do.  Billy was stiffed because they never intended to pay him, they intended to kill him.  So he hunts down the client to find out why.  That results in a couple of deaths and a brain-dead thug whose mother is outraged.  But the client gives-up the real money behind the hit, a billionaire who likes little girls.  And that angers Billy and his rescued girl.

One of the best books I've read this year.