Introduction: Immune checkpoint inhibitors targeting programmed death protein-1 and cytotoxic-T-lymphocyte-antigen-4 have revolutionized the treatment of various cancers. Despite their effectiveness, these therapies can lead to immune related adverse events. Observation: We reported a case of a 43year-old white woman who was referred to our department for a management of acute polyarthritis. She was followed for a relapsing metastatic melanoma (stage IIIb) by surgery and Pembrolizumab, an immune checkpoint inhibitor targeting programmed death protein-1. After receiving her 4 th cycle of this therapy she developed arthritis of the knees and the ankles, tenosynovitis and dry eyes with keratitis. After exclusion of other causes of polyarthritis such as connective-tissue disease, the diagnosis of rheumatologic immunerelated adverse events was retained. She was treated by 20 mg of prednisone daily, Pembrolizumab was discontinued. The evolution was favorable. Conclusion: Rheumatologic manifestations secondary to immune checkpoint inhibitors have been less well described in the literature. Their management requires the collaboration of oncologists and rheumatologists to limit the diagnostic delay and for an appropriate therapeutic choice according to their severity.