Cutting-edge research focuses on improving the delivery and efficacy of CAR T cell immunotherapies in solid tumors. Breakthroughs include gene engineering methods to armor CAR T cells with cytokine secretion control driven by endogenous promoters, enhancing targeted immunomodulation within tumors. Additional strategies aim to promote tertiary lymphoid structures and underscore unappreciated roles for natural killer cells in tumor immune landscapes. These innovations could expand CAR T cell utility beyond hematologic cancers.