Recently, the US Food and Drug Administration (FDA) approved the use of four anti-PD-1/PD-L1 drugs, including pembrolizumab, nivolumab, atezolizumab, and durvalumab, for the treatment of NSCLC, according to different corresponding immunohistochemical assays as companion or complementary diagnostic tests. This evidence concerns the gene CD274 and non-small cell lung carcinoma.