Second, although we have successfully adjusted for some important factors when estimating the adjusted association between ChE and OS of NSCLC, the information of some other potential confounding factors was unavailable, like tumor location, tumor size, smoking exposure level, immunohistochemistry of PD-L1 protein, molecular profiling, molecular target therapy, the risk of confounding bias cannot be precluded. The gene discussed is CD274; the disease is non-small cell lung carcinoma.