Pembrolizumab (a humanized IgG4κ mAb) is an anti-PD-1 ICI that the FDA has approved to treat various types of cancers, including metastatic melanoma [98,99], NSCLC [98], HNSCC [100], and solid tumors with MSI-H [101]. The gene discussed is PDCD1; the disease is non-small cell lung carcinoma.