Clinical trials have demonstrated that cutaneous irAEs are more likely to develop during combination anti-CTLA-4 and anti-PD-1 therapy (i.e., 40.3% of patients with melanoma receiving nivolumab and ipilimumab) than during monotherapy with anti-PD-1 (25.9% of patients with melanoma receiving nivolumab) or anti-CTLA-4 (32.8% of patients with melanoma receiving ipilimumab) [13]. The gene discussed is PDCD1; the disease is melanoma.