Skov BG et al. report that the expression of PD-L1 is only related to the clinical stage of non-small cell lung cancer, which suggests that a lower stage is associated with a lower prevalence of PD-L1 positivity [12], while Zhang et al. detected an association between high PD-L1 expression and male sex and smoking history [13]. This evidence concerns the gene CD274 and non-small cell lung carcinoma.