The INSPIRE trial evaluates nivolumab and ipilimumab combination therapy in mCRPC patients, focusing on subgroups with mismatch repair deficiency, high tumor mutational burden, CDK12 inactivation, and BRCA2 mutations. Results show significant efficacy in mismatch repair-deficient patients, emphasizing early molecular testing for checkpoint inhibitor therapy. Dual checkpoint inhibitors are more effective than monotherapy in specific subgroups, highlighting the need for broader genomic profiling in prostate cancer.