Prodigal son / Gregg Hurwitz.

Enhanced descriptions from Syndetics:

Forced into retirement, Evan Smoak gets an urgent request for help from someone he didn't even suspect existed--in Prodigal Son , the next New York Times bestselling Orphan X book from Gregg Hurwitz.

As a boy, Evan Smoak was pulled out of a foster home and trained in an off-the-books operation known as the Orphan Program. He was a government assassin, perhaps the best, known to a few insiders as Orphan X. He eventually broke with the Program and adopted a new name -- The Nowhere Man--and a new mission, helping the most desperate in their times of trouble. But the highest power in the country has made him a tempting offer--in exchange for an unofficial pardon, he must stop his clandestine activities as The Nowhere Man. Now Evan has to do the one thing he's least equipped to do--live a normal life.

But then he gets a call for help from the one person he never expected. A woman claiming to have given him up for adoption, a woman he never knew--his mother. Her unlikely request: help Andrew Duran--a man whose life has gone off the rails, who was in the wrong place at the wrong time, bringing him to the deadly attention of very powerful figures. Now a brutal brother & sister assassination team are after him and with no one to turn to, and no safe place to hide, Evan is Duran's only option. But when the hidden cabal catches on to what Evan is doing, everything he's fought for is on the line--including his own life.

Reviews provided by Syndetics

Library Journal Review

The sixth installment of the "Orphan X" series (after Into the Fire) picks up with Evan Smoak finding normalcy now that he has retired from being an assassin and equalizer for victims of injustice. All is well, until his mother--whom he has never met or spoken to--calls to request he assist a man named Andrew Duran. The ensuing events lead Evan into battles with a murderous brother-sister team, and clashes with powerful individuals who are unafraid to leverage high-tech military weaponry to kill ordinary citizens. This book touches on many emotional themes, including the meaning of family, as Evan establishes a relationship with his estranged mother and realizes that Andrew is an old friend from the orphanage. Twists and turns reveal even more connections between characters. Although this is the sixth book in the series, Hurwitz does a good job orienting new listeners within Evan's world. Fans of the series will appreciate how Evan's backstory is woven into the plot, providing details about his childhood and his selection for the Orphan program. Scott Brick delivers an unsurprisingly great performance that conveys the deep emotions of this book and hits the pace perfectly, with a snappy delivery. VERDICT Recommended for fans of the thriller genre; certainly a must-read for fans of Hurwitz.--Sean Kennedy, Univ. of Akron Lib., OH

Publishers Weekly Review

In bestseller Hurwitz's engrossing sixth Orphan X novel (after 2020's Into the Fire), former black ops assassin turned crime-fighting vigilante Evan Smoak is lured out of retirement by an unlikely individual: his mother. Given up when he was a newborn--and eventually recruited into the top-secret Orphan Program, where he was trained to be a government operative--Smoak is initially skeptical about his mother's sudden appearance. But the man she asks him to help turns out to be Andre, a kid he knew from childhood when they lived in a Baltimore group home. After witnessing a murder while working at an impound lot, Andre has disappeared, and Smoak soon becomes entangled in a grand-scale conspiracy involving cutting edge military technology. The pacing is breathtakingly brisk throughout, and the action is relentless, but the real hook is how much Smoak has matured emotionally, particularly in regard to his love interest Mia Hall, a district attorney who lives in Smoak's building, and Joey, his 16-year-old hacker protégée. This series continues to impress. Agent: Lisa Erbach Vance, Aaron Priest Literary. (Jan.)

Booklist Review

The Nowhere Man, the former government assassin otherwise known as Orphan X, is now Mr. Ordinary. He's retired from defending the innocent, a vocation he took up after he spectacularly resigned from government service. Well, it wasn't really Evan Smoak's choice to give up his altruistic line of work. It was more like an ultimatum from the American president: quit being a crusader-for-hire and face no charges for some recent activities. It's been a rough transition, too, from regularly putting his life on the line to spending his days as a wealthy man with nothing much to do. So when the woman who gave him up for adoption--presumably his mother, whom Evan never knew--asks him to help a man in trouble, Evan has mixed feelings, but he finds the prospect of getting back into action to be exhilarating. No matter the potential cost. From the first Smoak novel, 2016's Orphan X, this has been one hell of a series, each volume (this is number six) revealing more about Evan's deeply troubled past. The writing is pitch-perfect, too, which should come as no surprise to followers of Hurwitz's career (he's also written outstanding stand-alones, including They're Watching (2010) and The Survivor (2012). Nuanced and energetic, this is a great thriller.

Kirkus Book Review

Evan Smoak, the Nowhere Man, crashes out of retirement to battle a violent threat even less human than he is. Some agents are trained assassins. Evan is better described as engineered by Jack Johns, the Mystery Man who spirited him off from the Pride House Group Home when he was 12, honed the skills that made him a superlative killing machine, neglected less desirable aspects of his personality (like the ability to make small talk or show empathy), and turned him loose on a world in need of a superavenger. Now that he's finally hung up his blood-soaked laurels, Evan just wants to be left alone, but that's not on the agenda of Veronica LeGrande, the attractive 62-year-old who suddenly reveals herself as his mother so that she can beg him to protect Andrew Duran, a fellow alumnus of Pride House whom he hasn't seen for many years. It's a big ask, partly because Andre, as Evan once knew him, doesn't want to be protected and partly because the enemies Andre was exposed to in his unlikely role as the midnight guard on an impound lot are seriously mean. Shortly after Andre accepted the promise of $1,000 from brother-and-sister killers Declan and Queenie Gentner to tell them when Jake Hargreave picked up the Bronco he crashed and abandoned, Hargreave returned, Andre made the call, and Hargreave's throat was cut in the lot by a tiny, murderous drone. The man behind Mimeticom, drone king Brendan Molleken, has clearly studied all the villains in the James Bond movies, and there's no limit on the possible carnage when Evan meets Molleken, the Gentners, or any of those drones. Exhilarating pabulum for action fans weary of heroes who bother to maintain social lives. Copyright (c) Kirkus Reviews, used with permission.