This is a phase IIIb, interventional, single arm, multicentre study assessing the safety profile of durvalumab in combination with carboplatin-paclitaxel chemotherapy followed by durvalumab with olaparib as first-line treatment for patients with pMMR aEC as the primary endpoint. The study will include approximately 85 patients distributed in approximately 20 sites in Spain. The planned duration of patient recruitment is approximately 12 months. Each patient will be followed up from screening for 36 months, until end of study period, death, withdrawal from study or loss to follow-up; whichever occurs first. Enrolment will be opened to all eligible patients treated with durvalumab in combination with carboplatin-paclitaxel chemotherapy followed by durvalumab with olaparib as first-line treatment for patients with pMMR aEC. In addition, adequate tumour tissue before study entry, stool and blood sample collected will be required for central analysis to monitor the status of relevant biomarkers.