CD274 and cancer: Interestingly, preclinical TNBC studies demonstrated PARPi-mediated PD-L1 upregulation with expected attenuation of anti-tumor immunity, that PD-L1 blockade re-sensitized PARPi-treated cancer cells to T-cell killing, and the combination of PARPi and anti-PD-L1 therapy demonstrated greater antitumor activity and tumor control compared with each agent alone (127), further indicating a potential synergistic effect of combination DNA damage response inhibitors (DDRi’s) and ICI.