Twilight Heist by Katherine McIntyre

Heist rule number two? Never fall for a lone wolf.

A blast from Tuck’s circus past draws Tuck and the charming lone-wolf hacker, Leo, into a dizzying web of passion, secrets, and betrayal.

When the circus comes calling, Tuck is helpless to the lure, and this time, his old troupe’s in trouble. Their attempt to leave Reynauld Industries ended with a hit on them, courtesy of the deadly mercenary group, the Stockyard. Tuck can’t sit idly by, and as the resident stealth operator for the Outlaws, he’s in a unique position to help.
Leo’s a lone wolf hacker, and no amount of his best friend’s pleading, Tuck’s flirty smiles, or interesting jobs will sway him into working with the Outlaws. At least, until they land this one. After growing up in the hellish Stockyard, he’s wanted to take them down for years, and this is the Holy Grail of opportunities. Only problem? The Outlaws can never know about his history with them.
When Leo and Tuck start working together, a chemistry emerges that neither of them can deny. Leo’s mantra of “one and done” falters the moment Tuck shows him a care and steadfastness he’s never experienced before, and the more time they spend with each other, the more he doesn’t want to give up the first man he’s started to fall for. However, if the Outlaws discover his past or the Stockyard finds him first, Leo will end up one of the bloated corpses they’ve left lining the Chicago River.