To assess safety and additional efficacy parameters of the ipilimumab or nivolumab treatment in MCC, as well as to characterize potential biomarkers; secondary endpoints are: (i) adverse events according to CTCAE (Common Terminology Criteria for Adverse Events), Version 4.0 criteria, that are definitely, probably, or possibly related to the administration of ipilimumab, (ii) Overall survival rate at 12 months, defined as the number of patients surviving at 12 months after randomization divided by the total number of patients randomized, (iii) DFS rate at 12 months, defined as the number of patients alive and free of disease at 12 months after randomization divided by the total number of patients randomized.