The aim of our research was to evaluate the PD-L1 and PD-L2 expression on antigen-presenting cells, including myeloid and plasmacytoid DCs and MO/MA, in peripheral blood, peritoneal fluid, and tumor tissue, in relation to the clinicopathological characteristics and prognosis of ovarian cancer patients. The gene discussed is PDCD1LG2; the disease is ovarian cancer.