Zarya was sent on a mission to track down sombra that took some detective work
also soldier 76 was a vigilante tracking down those who caused the closure of overwatch.
I actually think there might be a character in the works like this, I remember reading something about a concept with an old man that has a cane that he releases nanobots out of or something... could just be rumors tho
The question kind of reminds me of the stories I'm writing for NaNoWriMo this year. They're about a cyborg detective with a revolver. So, basically, McCree if he were a PI instead of a bounty hunter.