These questions are being addressed by clinical trials of combined MDM2 inhibitor and monoclonal antibodies targeting PD-1/PD-L1 that have started for breast cancer, advanced solid tumours, liposarcomas, metastatic melanomas, and colorectal and renal cell carcinomas (NCT03566485, NCT03611868, NCT04785196, NCT03964233, NCT02890069). The gene discussed is MDM2; the disease is breast cancer.