Interestingly, recent studies reported that PKM2 was involved in the activation of various immune cells, including macrophages [11], dendritic cells [27], monocytes [28] and T cells [29]; however, the possible role of PKM2 in the regulation of the immune checkpoint PD-L1 in lung adenocarcinoma is unknown. The gene discussed is PKM; the disease is lung adenocarcinoma.