Epithelial high-grade serous and endometrioid ovarian carcinoma (HGOC) is the most common subtype of epithelial ovarian cancer (EOC) and is diagnosed in most patients at an advanced stage and is characterized by a poor prognosis. The standard of care for patients with newly diagnosed advanced HGOC consists of cytoreductive surgery and systemic treatment with platinum-based chemotherapy for more than three decades. Despite optimal treatment, approximately 70% of patients relapse within the first 3 years. With the introduction of homologous recombination deficiency (HRD) as a substantial predictive biomarker for HGOC, several PARP inhibitors are included in routine clinical practice in the treatment of EOC. Predictive biomarker studies are ongoing to evaluate specific patient groups that may benefit most from the use of PARP inhibitors. It is aimed to reveal the reasons for the development of resistance to platinum and PARP inhibitor agents and prevent the development of resistance with combination strategies.