Study of DNA Damage, Angiogenesis, and PD-L1 Inhibitors in Advanced Solid Tumors

This is a phase 2, single-centre, randomized, multi-cohort trial of subjects with advanced Mismatch Repair Proficient Colorectal Cancer (MMRp-CRC), Pancreatic Adenocarcinoma (PA), and Leiomyosarcoma (LMS). Subjects will be stratified based on their primary malignancy and enrolled into one of the following cohorts: * Cohort A: olaparib and durvalumab. * Cohort B: cediranib and durvalumab. Subjects will receive durvalumab through an intravenous line every 4 weeks. If subjects are assigned to the olaparib group, then they will take this pill twice a day continuously. If subjects are assigned to the cediranib group, then they will take this pill once a day for 5 consecutive days, and then have 2 consecutive days off, every week. Subjects will be enrolled in this trial to evaluate the changes in genomic and immune biomarkers in tumor, peripheral blood and stool samples, in addition to changes in radiomic profiles. About 90 people (45 subjects in each cohort) will be enrolled into this study at the Princess Margaret Cancer Centre.