Song of Sparrows and Sorrow by Liliana Hart

Nathan Locke has a very specific skill set, which is why he’s confused when Dynamis Security sends him on a mission to recruit an agent who doesn’t want to be found. Chasing her to hell and back doesn’t sound like his idea of a good time. Or maybe Alaska just seems like hell.
Eden Kane works for no one but herself. Not even when the most elite security company in the world wants her. She’s racing against the clock to hunt down the man who taught her everything she knows—her husband—known as Proteus in the terrorist world. He’s the man she was deceived into loving. The man who put a bullet in her chest and left her to die alone.
The search for Proteus leads to a discovery Eden and Nathan weren’t expecting, and thousands of lives are at stake. But trust doesn’t come easy, especially when you’ve been trained to lie as if your life depends on it.