Researchers at MIT validated a physical biomarker approach using suspended microchannel resonators to measure a T cell’s buoyant mass, reporting improved prediction of patient response to immune checkpoint blockade versus tumor mutational burden. The team tested the approach in a clinical study of 28 melanoma patients and reported better performance in predicting treatment response. The method reframes immune fitness as a measurable biophysical property that integrates more than gene-level proxies. The study also suggested utility beyond patient stratification, including helping assess the quality of T-cell products used in gene therapy manufacturing. For translational immuno-oncology, the practical takeaway is that “non-molecular” markers can complement molecular biomarkers—though scaling and external validation across cancer types will be the next hurdle.