The underlying mechanisms involved might be a low expression of PD‐L1, the downregulation of major histocompability complex molecules, and immunosuppression of regulatory chemokines in SCLC (He et al., 2017; Masuno et al., 1986; Tian et al., 2019; Zhu, Bagstaff, & Woll, 2006). This evidence concerns the gene CD274 and small cell lung carcinoma.