An FBI undercover agent infiltrates the mob and finds himself identifying more with the Mafia life--at the expense of his regular one.
Goodfellas
Catch Me If You Can
Spotlight
American Gangster
The Irishman
Dog Day Afternoon
Blow
Changeling
Lawless
Butch Cassidy and the Sundance Kid
In the Name of the Father
The Assassination of Jesse James by the Coward Robert Ford