Abstract: The present disclosure relates to methods and agents for enhancing the effect of immune effector cells, in particular immune effector cells that respond to interleukin-2 (IL2), for example effector T cells such as CD8+ T cells. Specifically, the present disclosure relates to methods comprising administering to a subject a polypeptide comprising IL2 or a functional variant thereof or a polynucleotide encoding a polypeptide comprising IL2 or a functional variant thereof and a polypeptide comprising type I interferon (IFN) or a functional variant thereof or a polynucleotide encoding a polypeptide comprising type I interferon or a functional variant thereof.