Notably, recent findings showed that PKM2 was closely positively related to PD-L1 expression in lung adenocarcinoma and colon carcinoma (Palsson-McDermott et al., 2017; Guo et al., 2019), while knockdown of PKM2 substantially inhibited PD-L1 expression in lung cancer cells (Guo et al., 2019). Here, PKM is linked to lung cancer.