Abstract Background Radiotherapy (RT) destroys cancer cells and activates the immune system while suppressing the immunity of tumor-associated tissues, including the tumor microenvironment (TME). However, to date, no anti-tumor therapeutic strategy that uses these immune mechanisms has been established. This study investigated changes in the immunity of the TME during standard radical RT for cervical cancer combined with external beam RT and brachytherapy and determined whether these changes affect prognosis. Methods Twenty-six patients who had completed radical RT for cervical cancer were categorized into the following two groups according to whether the cancer recurred and/or metastasized within 2 years after the start of treatment: treatment failure (n = 14) and treatment success (n = 12). We assessed the expression of programmed death 1, programmed death ligand 1 (PD-L1), cluster of differentiation (CD) 8, CD68, CD163, Forkhead box protein P3, and hypoxia-inducible factor-1α in the TME of cervical tissues collected periodically during treatment and evaluated the difference in expression rates of each marker between the success and failure groups and assessed its effect on prognosis. Results The expression levels of PD-L1 and CD163 in the TME in the treatment success group were lower than those in the treatment failure group at the midpoint during brachytherapy (p