When you get near this location, your Pip-boy will receive a signal. When you tune in to it, you’ll hear a looping radio program recording. The cinema has two movies playing but only with one projector active at a time. There are several ghouls distracted the movie and if you toggled the circuit breakers in the projector towers, they'll move to the other screen.
You can sneak inside the projector building and head to the third floor where you can find a red industrial chest and the Manager’s Key on top of it. You can use the key to open the storage room behind the movie screen to the south.
In the Cinema’s garage to the north, you’ll find a large toolbox and weapons workbench. The manager’s office has a Nuka-Cola inside, as well as a safe that can be opened using the Manager’s Key.