While most investigations studying response to immunotherapies in ovarian cancer focus on characterizing biomarkers and immune cell infiltration in primary solid tumors, we instead concentrated on developing PDOTS containing both circulating ascites tumors and immune cells collected from the same patients in the setting of relapsed HGSC disease (either with pathogenic BRCA1, BRCA2 mutations, or BRCA WT). Here, BRCA2 is linked to ovarian cancer.