The present disclosure provides methods and compositions for enhancing the immune response toward cancers and pathogens. It relates to immunoresponsive cells comprising antigen recognizing receptors (e.g., chimeric antigen receptors (CARs) or T cell receptors (TCRs)), and expressing increased level of IL-18. In certain embodiments, the engineered immunoresponsive cells are antigen-directed and resistant to immunosuppression and/or have enhanced immune-activating properties.