Checkpoint inhibitors like the PD-1 antibodies Pembrolizumab and Nivolumab represent standard of care for patients with metastasized melanoma. Numerous high quality studies demonstrate that endurance and resistance training in cancer patients is safe and elicits beneficial effects. However, there is no systematic experience with regard to exercise interventions in patients undergoing checkpoint inhibitor treatment. Therefore, the Sportivumab Study aimed to investigate safety, feasibility and effectivity of a 12 week combined resistance and endurance exercise intervention program during checkpoint inhibitor treatment. It is planned to enroll 40 patients. Participants will be randomized into an experimental and a wait-list control group (20 per group). The wait-list control group will receive the exercise intervention program after week 13 of enrollment.