GBM-bearing mice obtained a survival benefit from the absence of CD73 after treatment with anti-CTLA-4 and anti-PD-1.39 In this study, we identified tumor-infiltrating leukocyte phenotypes across four human tumors, glioma, colon cancer, breast cancer and lung cancer, by mIHC. This evidence concerns the gene PDCD1 and malignant colon neoplasm.