Immune checkpoint inhibitors (ICI) targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed death-ligand 1 (PD-L1) represent a major advancement in cancer therapy with significant improvements in overall survival and progression-free survival (PFS) for a broad variety of oncologic diseases such as non-small cell lung carcinoma (NSCLC) and melanoma [1–4]. This evidence concerns the gene PDCD1 and cancer.