Background: Carcinoma of the prostate is the most diagnosed tumors and the second top reason of cancer-related deaths in American men, The programmed death-ligand 1 (PD-1/PD-L1 pathway was a T-cell checkpoint pathway that sent repressing signals to T cells that can constrain immunity, PD-L1expression and relation to both pathological, clinical parameters and prognosis were studied in many cancers. proliferation cell nuclear antigen (PCNA)is proliferating cellular nuclear antigen, PCNA is an acidic nuclear protein, expressed mainly in phase S of the cellular cycle.We intended in this work to explore the immunohistochemical expression of PDL1 & (PCNA) in cancer prostate and correlate their expression with other clinicopathologic parameters. Methods: 46 cases of prostatic adenocarcinoma were collected from Pathology Department. Faculty of Medicine. Zagazig University between June 2018 to June 2020, using anti PDL1 & (PCNA) antibodies.Results: For PDL1 expression19 cases were positive (41.3%), showing membranous and cytoplasmic expression in tumor cells. Statistically significant relation was found between PDL1 expression and Age, grade, and stage, those who received chemotherapy. For PCNA expression 33 cases were positive (71.7%) showing nuclear expression. Statistically significant relation was found between PCNA expression and grade and stage and those who received chemotherapy. There is non-significant positive correlation between PDL-1 and PCNA.Conclusions: PDL1 may be a likely new marker or therapeutic goal for prostatic carcinoma cases, PCNA commonly used as a prognostic marker as an indicator of malignant cellular proliferation.