CD274 and neoplasm: Previous researches revealed that Treg cells were recruited into the human tumor microenvironment and inhibited T cell immunity to abolish the therapeutic efficacy of PD-L1, CTLA-4, and the TGF-β blockade, regardless of whether they were live or apoptotic (Zou, 2006; Maj et al., 2017; Principe et al., 2021).