Targeted therapies for use in clinical studies, such as those in immunooncology (I-O), are the future of pharmaceuticals. Critically assessing the efficacy and safety of a targeted molecule in I-O trials is essential. Li Zhou Ph.D., Christina D. Swenson Ph.D., Karen J. Quadrini Ph.D., Thomas W. Mc Closkey, Ph.D., and Krista D. Buono Ph.D. at ICON delve into flow cytometry being a sophisticated technology that can provide specific information on how biologics and other targeted therapies interact with living cells on a cellular level in clinical trials.