Chimeric antigen receptor T (CAR T) cell therapy has revolutionized the management of lymphoid malignancies. However, it is still in its early phase and is facing many obstacles in solid tumors. Therapeutic challenges in solid tumor lead to tumor target diversification and drive new innovations for the improvement of clinical efficacy. This review showcases early clinical works and sheds light on the most notable successes, drawbacks, and strategies employed to allow CAR T therapy to go full speed ahead.