This is a randomized, open-label Phase 2 study to investigate the efficacy and safety of UV1 vaccination in combination with nivolumab and ipilimumab as first line treatment of adult patients with histologically confirmed unresectable metastatic melanoma.

154 Patients in the experimental arm will receive 8 UV1 vaccinations over 4 cycles of nivolumab and ipilimumab. Patients in the control arm will receive 4 cycles of nivolumab and ipilimumab. Patients in both arms will start maintenance therapy 6 weeks after the last dose of induction therapy, nivolumab at a dose of 480 mg every 4 weeks.

All patients will be followed up until death or until the end of the study.