In our study, we evaluated the expression of PD-L1 and PD-L2 on antigen-presenting cells, e.g., myeloid and plasmacytoid DCs and monocytes/macrophages in the three different OC environments, i.e., peripheral blood, peritoneal fluid, and among ovarian cancer infiltrating cells (tumor tissue). This evidence concerns the gene PDCD1LG2 and ovarian cancer.