I think the communicator hand held and the wrist communicators in the original Star Trek series are the first I remember.....1970s. There was no such thing as a cell phone at that time but look at the similarity.
The first one that I remember seeing was in Bosley's car on Charlie's Angels. That was in an episode that aired in either 1976 or 1978. In a movie though, no clue.
This post was edited by Benedict Arnold at February 18, 2019 5:59 AM MST
The earliest James Bond films had him making use of a car phone. The phones still had a cord but what in the world was the phone line connecting to from a moving vehicle? Just a fashionable cord I guess.