Some immune checkpoint inhibitors, such as atezolizumab, which is a humanized IgG1 antibody to PD-L1, and durvalumab, which is a fully human immunoglobulin G1 (IgG1) antibody to PD-L1, are currently used for SCLC treatment in combination with chemotherapy [17]; however, according to a phase III clinical trial results, their therapeutic efficacy is not dramatic [18]. This evidence concerns the gene CD274 and small cell lung carcinoma.