PDCD1 and neoplasm: Elevated PD-1 levels in TAMs have been correlated with reduced phagocytosis, impaired activation, and enhanced tumor progression (Gordon et al., 2017; Kono et al., 2020; Xu et al., 2023; Zhang et al., 2023) Given this background, we investigated whether MCF-7 EVs could induce PD-1 expression in macrophages, potentially contributing to immune evasion.