T-cell transfer therapies have not yet been successfully applied to solid tumors because T cells do not readily penetrate and persist in solid tumor masses for long periods of time, and because their activity is attenuated by an immunosuppressive tumor microenvironment. One way to overcome these limitations could be to couple T cell transfer therapies with cytokine therapy. However, a serious drawback of this approach is the significant side effects resulting from cytokines circulating freely in the body, leading to toxicity and potentially fatal inflammatory syndromes. Now, researchers have developed a nanotechnology-based solution to these problems. The method uses an unnatural sugar that is absorbed and embedded in the outer coating of T cells, which can then be used to anchor cytokines. The concentrated cytokines improve T-cell function locally without producing unwanted systemic side effects. In mice with melanoma, the approach also stimulated the host immune system against tumor cells, which inhibited tumor growth. As an adjunct to CAR-T cell therapy, it resulted in complete regression of lymphoma tumors at otherwise non-curative cell doses.