CD274 and neoplasm: PD-1 receptor is an inhibitor of both adaptive and innate immune responses and can be expressed on CD8+ T cells, CD4+ T cells, and Tregs in ovarian tumors, whereas PD-L1 is expressed on activated T cells, tumor-infiltrating macrophages or fibroblasts, contributing to tumor immune escape.40 However, the expression of PD-1 and PD-L1 in HGSC ascites and its correlation with survival has not yet been fully investigated.