A display device according to an embodiment includes: a display, a communication interface comprising communication circuitry configured to communicate with at least one of a first control device including a first key and a second control device including the first key, and at least one processor, individually and/or collectively, configured to execute at least one instruction to cause the display device to: receive a first control signal corresponding to the first key, perform a first operation to output a first full screen by executing the first control signal based on the first control signal being received from the first control device while first content is being played, and perform a second operation different from the first operation to output a second full screen different from the first full screen based on the first control signal being received from the second control device while the first content is being played.