PDCD1 and glioma: For example, with the success of the programmed cell death protein 1 (PD‐1) and programmed cell death 1 ligand 1 (PD‐L1) blockade treatment in melanoma, renal‐cell carcinoma and non‐small‐cell lung cancer,6, 7, 8 immunotherapy represents a new revolutionary strategy in glioma.9