Hurwitz, Gregg. Orphan X novel.

Title from web page

Once a black ops government assassin known as Orphan X, Evan Smoak left the Program, and reinvented himself as someone who will risk everything to help those who have nowhere else to turn. Now struggling with an unexpected personal crisis, Evan goes back to the very basics of his mission, and this time, the truly desperate is a little girl who wants him to find her missing dog. Not his usual mission, but it quickly explodes into his biggest mission yet, one that finds him battered between twisted AI technocrat billionaires, a mysterious female assassin who seems a mirror of himself, and gut-wrenching personal stakes. Evan's mission pushes him to his limit; he must find and take down the assassin known only as the Wolf, before she succeeds in completing her mission and killing the people who can identify her; a teenaged daughter of her last target, and Evan himself. Matched in skill and instinct, Evan must outwit an opponent who will literally stop at nothing if he is to survive

Read by Scott Brick