The AlphaLISA® human PD-1/PD-L1 binding kit is designed for the detection of binding activity between human PD-1 and PD-L1, using a fast and simple homogeneous AlphaLISA assay (no wash steps). This assay can be used to screen for small molecules that inhibit binding, as a competitive ligand binding (CLB) assay to screen therapeutic blocking antibodies, and for potency assays.