CD68 and neoplasm: In order to see whether specific types of infiltrating leukocytes contributed to PD-L1 and PD-1 expression on tumor cells, we determined the presence of different subsets of T cells and myeloid cells in the same CM, by performing immunofluorescence (IF) staining according to previously described techniques [16]: we measured the numbers of CD3, CD3+CD8+, CD3+CD8-, CD3+CD8-Foxp3+ and CD3+CD8-Foxp3- T cells, and CD68 (macrophages) and CD68+CD163+ (M2 macrophages) within tumor areas of 26 primary CM sections.