Scorpio (1973)

Cross (Burt Lancaster) is an experienced assassin for the CIA who decides he's quitting the business. When he announces his intentions, however, the CIA decides they'd rather have him dead than retired. They assign Scorpio (Alain Delon), a French assassin whom Cross has mentored for years, to do the job. A complicated game of cat and mouse follows, during which Cross relies on his many contacts and years of experience to elude the man he's taught everything he knows.