Understanding the signaling pathways that biomarkers can activate can aid in the development of checkpoint immunotherapies. Surface Plasmon Resonance (SPR) is a common technique used to identify and elucidate biomarker interactions, signaling pathways, mechanisms of interaction, drug discovery, and the development of therapeutics. It provides a label-free, real-time method for determining binding kinetics and binding affinity of key biomolecular interactions. Systems like Alto from Nicoya Lifesciences, the world’s first digital SPR instrument to integrate digital microfluidics and nanotechnology, can measure biomolecules in pM concentrations in various sample matrices with high specificity while offering the versatility of working with a range of biomolecule types.