The high recurrence and low responsiveness to immunotherapy make ovarian cancer (OC) the most lethal gynecological malignancy. Tumor microenvironment is critical in risk stratification and the discovery of molecular targets. We developed a prognostic classification for OC, which could also predict the prognosis of other gynecological cancers including breast cancer, endometrial cancer, and cervical cancer. Somatic mutation, hallmark pathways, and immune landscapes were characterized. Integrative analysis of immune checkpoints and multiple immune signatures revealed the low-risk group responds better to immune checkpoint inhibitors, which was validated by an external immunotherapeutic cohort (IMvigor210). Single-cell RNA sequencing (scRNA-seq) confirmed the high expression of SERPINB1 and SERPINB9 in dendritic cells, and AlphaFold2 was used to infer their 3D protein structures. Putative molecular compounds binding to SERPINB1/SERPINB9 were predicted by virtual screening.