Emerging studies have suggested that glioma has a suppressive immune microenvironment, which further inhibits the response to immunotherapy represented by anti-PD-1/PD-L1 and anti-CTLA4 (Jackson, Choi & Lim, 2019; Lim et al., 2018; Xu et al., 2020). The gene discussed is PDCD1; the disease is glioma.