PDCD1 and neoplasm: To elucidate the T cell immune microenvironment of lactate-augmented anti-tumor immunity, we analyzed CD3+ T cells from MC38 tumors and tumor draining lymph nodes (DLNs) using single cell RNA sequencing analysis (sc-RNAseq, 10x genomics platform) after treatment by anti-PD-1 alone or combined with lactate (Fig. 3a).