Although immunohistochemistry (IHC) of PD-L1 expression has been widely applied clinically [2], there remains a lack of published studies on the prevalence of PD-L1 expression in a large-scale eastern-Asian cohort and the concordance of PD-L1 expression in patients with multiple lung cancers or repeated PD-L1 testing. The gene discussed is CD274; the disease is lung carcinoma.