CD274 and endometrial cancer: ROS-elevating hypoxic conditions, that promote both expression, activation and stabilization of the transcription factors HIF-1α, NF-κB and Yes-associated protein 1 (Yap1) (Kang et al., 2020), are frequently associated to elevated membrane expression of PD-L1 on cancer cells of solid tumors such as pulmonary pleomorphic carcinoma (Chang et al., 2016), endometrial cancer (Tawadros and Khalafalla, 2018) and non-small-cell lung cancer (Guo et al., 2019).