Cytokine receptors are proteins found on the surface of cells that bind to cytokines, which are signaling molecules involved in immune responses and cell communication. When a cytokine binds to its receptor, it triggers a series of cellular responses, influencing processes like inflammation, cell growth, and differentiation. These receptors are crucial for the immune system's function, as they help regulate how cells respond to infections and other stimuli. Different types of cytokine receptors exist, each specific to certain cytokines, allowing for precise control of immune responses and maintaining homeostasis in the body.