ABSTRACT Merkel cell carcinoma (MCC) is a rare and difficult-to-treat cutaneous malignancy with a poor prognosis. Treatment protocols for localized MCC are well established. Until recently, metastatic MCC has generally been treated with chemotherapy, which was often associated with poor clinical responses and significant toxicity. In this report, the case of a patient with metastatic MCC who received avelumab, an immune checkpoint inhibitor, after an inadequate response to first-line radiotherapy and chemotherapy, is presented. Nine months after the initiation of the treatment with avelumab, the patient achieved a partial remission with no treatment-related adverse events. After a follow-up of 17 months, a systematically ongoing partial response was reported. In conclusion, this case study offers a clinical insight into the patient’s case and highlights the importance of immunotherapy as a first-line therapy for metastatic MCC.