Immunotherapeutics include drugs and biologics that render therapeutic benefit by harnessing the power of the immune system. The promise of immune-mediated therapies is target specificity with a consequent reduction in off-target side effects. Recent scientific advances have led to clinical trials of both active and passive immunotherapeutic products that have the potential to convert life-ending diseases into chronic but manageable conditions. Clinical trials investigating immunotherapeutics are ongoing with some trials at advanced stages of development. However, as with many products involving novel mechanisms of action, major regulatory and scientific issues arising with clinical use of immunotherapeutic products remain to be addressed. In this review, we address issues related to different immunotherapeutics and provide recommendations for the characterization and evaluation of these products during various stages of product and clinical development.