CD274 and neoplasm: Tumor-derived exosomes or so-called apoptotic bodies have protumorigenic and prometastatic properties (Hoshino et al. 2015, Becker et al. 2016) and have been shown to package and present both TGFβ (Xie et al. 2009, Wada et al. 2010, Webber et al. 2010) and PD-L1 (Poggio et al. 2019) to immune and malignant cells to drive tumor progression.