PDCD1 and central nervous system cancer: In the GL261 glioma model, which was defined as an immunotherapy-sensitive glioma model, increased expression of M1 macrophage markers (Tnfa, Irf7, and Ifng) and decreased expression of M2 macrophage markers (Arg1, Cd206 and Cd163) were found after treatment with anti-PD1 immunotherapy (Fig. 6E, 6G and 6M-R).