Yang et al. demonstrated that PD-L1 and CD63 colocalized in MVBs originating from the human breast cancer cell line MDA-MB-231 and human breast cancer tissues via immunofluorescence staining and immunohistochemistry, respectively, thereby confirming that breast cancer cells can also secrete PD-L1-carrying exosomes [123]. The gene discussed is CD274; the disease is breast carcinoma.