Comprehensive Analysis of Predictors of the Treatment With Pembrolizumab and Olaparib in Patients With Unresectable or Metastatic HER2 Negative Breast Cancer and a Deleterious Germline Mutation or a Homologous Recombination Deficiency (COMPRENDO

This study will examine the combination of pembrolizumab and olaparib in three populations. * Cohort 1: aBC patients with a germline mutation in BRCA1 or BRCA2, * cohort 2: aBC patients with a germline mutation in one of the moderate penetrance homologous repair genes (ATM, BARD1, CHEK2, FANCC, PALB2, RAD51C, RAD51D, SLX4, XRCC2), and * cohort 3: aBC patients with a HRD as assessed by whole genome sequencing.