Chimeric antigen receptor (CAR) T-cell therapy has shown remarkable responses in B-cell malignancies. However, many patients suffer from limited response and tumor relapse due to lack of persisting CAR T cells and immune escape. These clinical challenges have compromised the long-term efficacy of CAR T-cell therapy and call for the development of novel CAR designs. We demonstrated that CAR T cells secreting a cytokine interleukin-36γ (IL-36γ) showed significantly improved CAR T-cell expansion and persistence, and resulted in superior tumor eradication compared with conventional CAR T cells. The enhanced cellular function by IL-36γ was mediated through an autocrine manner. In addition, activation of endogenous antigen-presenting cells (APCs) and T cells by IL-36γ aided the formation of a secondary antitumor response, which delayed the progression of antigen-negative tumor challenge. Together, our data provide preclinical evidence to support the translation of this design for an improved CAR T-cell-mediated antitumor response.