For example, while PD-1/PD-L1 inhibitors have shown significant success in other cancers such as melanoma and NSCLC [48,49], their efficacy in ovarian cancer is limited [50], which is complicated by the fact that tumour PD-L1 expression does not reliably predict treatment responsiveness in any of these tumour types [51,52]. This evidence concerns the gene CD274 and ovarian cancer.