PDCD1 and neoplasm: In an experimental study in experimental pancreatic cancer on mice, the combination of anti-PD-1 with anti-CTLA-4 resulted in higher T cell infiltration and tumor response, while blocking CSF-1/CSF-1R resulted in elevated PD-1/PD-L1 expression on TAMs and increased CTLA-4 expression on CD8+ T cells [131].