In the research by Masuda et al16 into NSCLC with epidermal growth factor receptor (EGFR) mutation and high PD-L1 expression, PD-L1 expression level correlated with the efficacy of PD-1 inhibitors and could, therefore, be applied for assessment of PD-1 inhibitor efficacy. Here, PDCD1 is linked to non-small cell lung carcinoma.