Lee Child crafted an incredible world with the stories of Jack Reacher and Prime Video has beautifully adapted the stories of the 110th Special Investigations Unit. While Season 1 of Reacher introduced audiences to the towering veteran Jack Reacher (Alan Ritchson), Season 2 expands on his backstory with the military. This deepens the world of Reacher and allows more characters to feature in the series. These additional characters not only enhance the story, but they can give fans a look into who Jack Reacher is.
Source:https://www.cbr.com/reacher-110th-special-investigations-backstory/