The anti-programmed cell-death-1 antibody, nivolumab, has been recently approved for the treatment of advanced non–small cell lung cancer. Although, today, immune-related adverse effects such as dermatologic, digestive, hepatic, and endocrine toxicities are well-known with immune checkpoint inhibitors, rheumatic diseases are less well described. Herein, we report the case of a patient without a history of arthritis who developed polymyalgia rheumatica after 13 cycles of nivolumab used for the treatment of advanced non–small cell lung cancer. Laboratory evidence of inflammatory syndrome, articular echography, and clinical presentation with classical symptoms and also distal manifestations were suggestive of this chronic inflammatory disorder. Because of a relevant pain, clinicians were forced to suspend immunotherapy. Nevertheless, due to glucocorticoid therapy, the patient’s symptoms have decreased progressively. Moreover, nivolumab was reintroduced 8 weeks later, whereas prednisone (10 mg) was continued, without any recurrence symptoms. To conclude, our case suggests that polymyalgia rheumatica might be a very disabling anti-programmed cell-death-1 immune-related adverse effect.