In addition, several studies have revealed that PKM2, which converted phosphoenolpyruvate into pyruvate, was highly expressed in tumors (Christofk et al, 2008; Elf and Chen, 2014) and enhanced PD-L1 expression in both tumor and immune cells via epigenetic mechanisms (Palsson-McDermott et al, 2017). Here, PKM is linked to neoplasm.