Sivapiragasam A, Kumar PA, Sokol ES, et al. - Researchers explored the prevalence as well as the distribution of immunotherapy responsiveness‐associated biomarkers, using a large dataset of female metastatic breast cancers (MBCs) profiled with comprehensive genomic profiling (CGP). From 3,831 consecutive MBCs, DNA extraction was performed: 1,237 (ER^pos [estrogen receptor positive] /HER2^neg), 1,953 ER^neg/HER2^amp, and 641 triple‐negative breast cancer (TNBC). The markers of potential immune checkpoint inhibitor (ICPI) advantage were: CD274 (PD‐L1) amplification (1%–3%), BRAF GA (genomic alteration) (1%–4%), tumor mutational burden of ≥ 10 mutations/megabase (8%–12%), microsatellite instability‐high (0.1%–0.4%), PBRM1 GA (1%), and positive PD‐L1 staining of immunocytes ranging from 13% in ER^pos/HER2^neg and 33% in ER^neg/HER2^amp to 47% in the TNBC group. Inactivating STK11 GA (1%–2%) and MDM2 amplification (3%–6%) were identified as the potential markers of ICPI resistance. The requirement for development as well as utilization of biomarkers, to guide the use of ICPIs for patients with MBC, was supported by the demonstrations of clinical advantage of immunotherapy in MBC. Findings demonstrated the potential of CGP not only in identifying GA linked to response and resistance to ICPI in MBC but also in guiding therapy selection.