PDCD1 and neoplasm: Since the ICI failure in PDAC is still an unresolved issue, and given the role of CD163+ M2-like macrophages as a prominent cell population in the TME of PDAC (10, 24, 45), a better understanding of how stromal macrophages impact the PD-1/PD-L1 axis and activity of CD8+ T cells in this tumor entity is greatly needed.