Recently, the relationship between the immune system and cancer has become increasingly elucidated, leading to an emerging branch of immunotherapy called CAR T cell therapy. T cells collected from a patient are genetically engineered to express a chimeric antigen receptor (CAR) designed to recognize a tumor-associated antigen and elicit T cell activation. CAR T cell therapy has had remarkable success for hematological malignancies, but emerging obstacles impede its expansion to other indications. Often, complications relate to lack of control over CAR T cell activity, leading to safety issues or limited efficacy. To address these issues, two novel CAR platforms were developed that improve upon control and specificity. First, CARs targeting dominant T cell malignant clones identified by the variable regions of the TCR (TCRvβs) were designed. TCRvβ-CARTs exhibited minimal on-target, off-tumor activity that currently limits approaches for T cell malignancies. This is evidenced in specificity and efficacy against target cells, including cell lines and patient samples, in vitro as well as in disseminated mouse models. TCRvβ-CARTs precisely target malignant clones to overcome current limitations to CAR T cell therapy for T cell malignancies. Secondly, a universal immune receptor (UIR) platform was developed in which the tumor-targeting extracellular portion of the CAR was exchanged for a single-chain variable fragment (scFv) specific for a tag, allowing the CAR T cells to remain dormant until introduction of tagged antibodies. Here, an scFv specific for the metal chelating molecule DOTA was utilized. Tumor-specific molecules against seven antigens were tagged with DOTA and elicited dose-dependent cytotoxicity in vitro. Additionally, target cells were eliminated in mice bearing HER2+ tumors. Finally, components of the UIR and the targeting ligands were modified to provide a toolkit for a fully adaptable system. The DOTA UIR platform offers increased versatility of tumor targeting and control of activity. Overall, both TCRvβ-CAR and DOTA-UIR platforms represent innovative approaches to overcoming the current limitations of CAR T cell therapy through improved control and specificity.