Researchers reported post-marketing bridging studies confirming that two commercially available companion diagnostics reliably identify patients with dMMR/MSI-H tumors eligible for pembrolizumab. The results, published in BMC Cancer, detail how regulators validated diagnostic assays used in routine practice against the original clinical trial assay backbone. The work highlights a practical bottleneck in tumor-agnostic oncology: ensuring that assay performance translates from trial conditions to real-world deployment. If the bridging evidence holds across settings, it can support more scalable implementation of biomarker-driven immunotherapy and reduce eligibility uncertainty at the testing stage.