Doing a quickie search Cube looks interesting.
I’m not prone to it, but I have to admit I’m getting claustrophobic reading about all these movies!
Most of Le Trou (1960) takes place in a prison cell.
The Graceful Brute (1962) is a Japanese black comedy set almost entirely in the apartment of a family so greedy, they act like it’s an entitlement. They meet their match in the title character, played by the gorgeous Ayako Wakao.
It’s been a long time since I’ve seen it, but I recall the bulk of The Offense (1973) taking place in an interrogation room.
The Iceman Cometh (1973) takes place entirely in a bar.
The TV movie Steambath (1973) takes place in…well, see if you can figure it out.
A chunk of the opening of Out of Sight (1998) takes place in a car trunk.
Not exactly what you’re looking for, but Jim Jarmusch’s “Night On Earth” are five episodes playing in taxis in LA, Rome, Paris, Helsinki and New York.