Consequently, ICIs, such as anti-PD-L1 monoclonal antibodies (mAbs-Atezolizumab, Avelumab, and Durvalumab), anti-PD-1 mAbs (Nivolumab and Pembrolizumab), and anti-CTLA-4 mAbs (Ipilimumab) led to marked therapeutic efficacy in melanoma, as well as lung, head and neck, and urothelial cancers [23,24,25]. The gene discussed is PDCD1; the disease is melanoma.