Endometrial cancer (EC), the most common gynecological malignancy in developed countries, presents a significant challenge in its advanced or recurrent stages. While early-stage EC is often curable, advanced or recurrent EC has a poor prognosis, necessitating novel therapeutic strategies. In recent years, immune checkpoint inhibitors (ICIs) have emerged as a promising therapeutic strategy for EC, particularly in tumors harboring mismatch repair deficiency (MMRd) or high microsatellite instability (MSI-H). Subsequently, the combination of ICIs and lenvatinib, a multi-kinase inhibitor, has significantly improved survival of patients with previously treated recurrent EC, irrespective of MSI status. Besides, several phase III trials demonstrated the significant antitumor efficacy of combining ICIs plus first-line chemotherapy, followed by maintenance of the combination of ICIs with/without poly ADP ribose polymerase (PARP) inhibitors for both MMRd and mismatch repair proficient (MMRp) EC. This review summarizes the current landscape of ICIs in EC, including mechanisms of action, key clinical trials, emerging predictive biomarkers, real-world evidence, and ongoing research. Future perspectives focusing on combination therapies, biomarker-driven patient selection, and novel immunotherapeutic approaches are also discussed.