The present disclosure provides for methods of improving the efficacy of T cells. In an aspect, the disclosure further provides for methods of enhancing the persistence of T cells for adoptive cell transfer or therapy (ACT). Cytokine sensitivity assays (CSA) and associated methodology capable of predicting the persistence of adoptively infused T Cells are further provided for by way of the instant disclosure. The disclosure also provides for methods of treating cancer in a subject in need thereof as well as T cells populations produced by methods described herein.