PDCD1 and glioblastoma: Several studies have shown that TMB is a very effective prognostic marker and is associated with immune checkpoints (PD-1, PD-L1, etc.)in many cancers, including GBM (Yarchoan et al., 2017; Litak et al., 2019; Ready et al., 2019; Wang and Li 2019; Marabelle et al., 2020; Yin et al., 2020).