Given the established role of the PD-1/PD-L1 axis in promoting chemoresistance in various cancers including breast cancer, B-cell lymphoma, and small cell lung cancer, a study by Yati et al. uncovered that OS cells treated with doxorubicin can prompt the release of exosomes that mediate PD-L1 expression in OS cells through IL-1 signaling pathway [111,112,113,114]. Here, CD274 is linked to breast cancer.