Two-hander

A two-hander is a term for a play, film, or television programme with only two main characters.

[1] The two characters in question often display differences in social standing or experiences, differences that are explored and possibly overcome as the story unfolds.

[2][3] Instances of two-handers may include theatre, film, television episodes, television series, and radio.

The two characters Ben and Gus in Harold Pinter's The Dumb Waiter