The emergence of immune checkpoint inhibitors (ICI), which includes targeted antibodies against programmed cell death protein 1 (PD-1), programmed cell death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA4) has increased the survival of metastatic NSCLC patients, but, only a small number of metastatic patients achieve long-term survival [5]. The gene discussed is PDCD1; the disease is non-small cell lung carcinoma.