Endometrial cancer is the most common gynecologic malignancy. To optimize treatment, avoiding overtreatment in low-risk patients and developing new therapies for high-risk cases are essential. The Cancer Genome Atlas (TCGA) identified four molecular clusters with distinct genomic features. The association between prognosis and the classification of molecular subtypes has been validated in multiple cohorts of endometrial cancer with various testing methods for surrogate markers. It is now incorporated into the WHO fifth edition classification using surrogate markers: POLE-mutated (POLEmut), mismatch repair-deficient (MMRd), no specific molecular profile (NSMP), and p53 abnormal (p53abn). Based on these findings, the 2023 FIGO staging system includes molecular subtypes for the first time. It also integrates pathological risk factors such as histological type, grade, lymphovascular space invasion (LVSI), and micrometastasis, highlighting the need for detailed evaluation. The relationship between molecular subtypes and prognosis is becoming central to treatment decisions. Molecular-based adjuvant therapies and novel treatments for advanced or recurrent disease are under development, with growing expectations for personalized care in endometrial cancer.