CD274 and neoplasm: Chang et al. confirmed that myelogenous suppressor cells (MDSCs) can promote the transformation of immature B cells into Bregs in the tumour microenvironment, and in this process, MDSCs can mediate the transfer of membrane‐bound PD‐L1 to Bregs in the form of secretory vesicles, thus increasing the expression of PD‐L1 in Bregs and mediating immunity through the PD‐L1 pathway to inhibit T‐cell function.18