Immune checkpoint functional assays are essential for evaluating the effects of immune checkpoint inhibitors on T cell activation, proliferation, and cytokine release. These assays help researchers understand how immune checkpoint pathways regulate immune responses, particularly in cancer immunotherapy. Techniques such as flow cytometry, ELISA, and cytotoxicity assays are commonly used to assess the efficacy of therapeutic antibodies and small molecules. By optimizing these assays, scientists aim to improve immunotherapy strategies and enhance patient outcomes in oncology and autoimmune disease treatment.