PDCD1 and glioblastoma: Besides, we noticed that there was a relatively weak correlation between the expression of PD-1 and all the immune cells in CHOL, Glioblastoma Multiforme (GBM), Acute Myeloid Leukemia (LAML), LGG, and PCPG (R < 0.7), whereas the UVM showed a strong correlation between PD-1 expression and six types of immune cells (T cells, CD8+ T cells, cytotoxic lymphocytes, NK cells, monocytic lineage, and myeloid dendritic cells).