In the absence of BRAF mutation, first-line therapy of metastatic melanoma is limited to two options: monotherapy with anti-PD-1 agents (nivolumab or pembrolizumab) or a combination of an anti-PD-1 agent and an anti-CTLA-4 agent (nivolumab and ipilimumab) [6]. Here, CTLA4 is linked to metastatic melanoma.