CD274 and cancer: Immune checkpoint inhibitors (ICIs) are among the most promising methods for cancer treatment, but based on several clinical trials, their effect in ovarian cancer is not good, and data from the pembrolizumab standalone clinical trial Keynote-100 showed that the ORR was 8% in PD-L1-negative patients and 18% in PD-L1-positive patients (Matulonis et al., 2019).