CD274 and cancer: A relatively high co-expression of PD-L1 and PD-L2 has also been observed in a number of cancers such as classical Hodgkin’s lymphoma, primary mediastinal large B-cell lymphoma, T-cell lymphoma, triple-negative breast cancer, gastric carcinoma, melanoma, squamous carcinoma of the lung, head and neck, and cervix and vulva, bladder cancer, and hepatocellular carcinoma [83,87,88,89].