The effectiveness of immunotherapy for cervical adenocarcinoma (CA) has not been demonstrated yet. Programmed cell death 1 (PD-1), programmed cell death-ligand 1 (PD-L1), and CD8 may be used as biomarkers of response to immune therapy in CA patients. In the present study, we aimed to investigate whether the expression levels of PD-1, PD-L1, and CD8 can predict the prognosis of patients with CA and their response to immune checkpoint inhibition therapy. In the present study, the clinical stage for all 82 patients with cervical adenocarcinoma was classified according to the guidelines of the International Federation of Gynecology and Obstetrics (FIGO); there were 5, 48, 5, 14, 8, and 2 patients with stage IA, IB, IIA, IIB, IIIB, and IVB disease, respectively. The levels of PD-1, PD-L1, and CD8 were analyzed by the immunohistochemical analysis of the formalin-fixed paraffin-embedded tumor samples. The correlation between the expression levels and patient prognosis was analyzed using the Kaplan-Meier method and univariate and multivariate Cox proportional hazard regression models. We observed a significant inverse correlation between the expression of PD-1 and CD8 (p = 0.001, chi-square test). We also found a significant inverse correlation between the expression of PD-L1 and CD8 (p = 0.027). The overall survival and progression-free survival rates were significantly worse in patients with positive PD-1 expression (p = 0.031; p = 0.087, respectively). Our results suggest that a high PD-1 expression is associated with a poor prognosis in patients with CA. Further research is necessary to identify the molecular mechanisms that mediate this association.