CD274 and cancer: We show that: (1) CF33-hNIS-antiPDL1 effectively infects and kills human peritoneal GCPM cancer cells, (2) anti-PD-L1 scFv expressed by the virus-infected cancer cells blocks PD-L1 on cancer cells, and (3) CF33-hNIS-antiPDL1 decreases immune inhibitory factors and growth factors to create an anti-tumor immune microenvironment.