The objective of this study was to analyze, by immunohistochemistry, the expression of PD-1, PD-L1, CD8, MLH1, MSH2, MSH6, PMS2, and p53 in paraffin-embedded tumor samples from patients with advanced serous ovarian carcinoma and to correlate these expression profiles with the clinicopathological data of the patients. Here, PDCD1 is linked to ovarian serous carcinoma.