Immunotherapy in head and neck cancer introduces novel tumor response patterns and immune-related toxicities that can mimic disease progression and challenge traditional imaging assessment. Accurate interpretation requires in-depth understanding of immune checkpoint inhibitors, chimeric antigen receptor-T cell therapy, and oncolytic virus treatments, along with recognition of atypical responses such as pseudoprogression, hyperprogression, dissociated response, and durable response. Incorporating modified imaging criteria like iRECIST and imPERCIST enhances diagnostic accuracy. Radiologists play a vital role in identifying immune-related adverse events across organ systems, guiding appropriate management, and supporting continued treatment when effective.