Case Study: Flow cytometry-based assay to characterize binding activity of PD-L1xCSPG4 BsAb [93]: To improve antibody-therapy efficacy in patients with advanced melanoma, the authors developed a BsAb, PD-L1xCSPG4, to selectively reactivate T cells by directing PD-1/PD-L1 disrupting activity to chondroitin sulfate proteoglycan 4 (CSPG4)-expressing tumor cells. Here, CSPG4 is linked to melanoma.