show Abstracthide AbstractReversing the dysfunctional T cell state that arises in cancer and chronic viral infections is the focus of therapeutic interventions; however, current therapies are effective in only some patients and some tumor types. To gain a deeper molecular understanding of the dysfunctional T cell state, we analyzed population and single-cell RNA profiles of CD8+ tumor-infiltrating lymphocytes (TILs) and used genetic perturbations to identify a distinct gene module for T cell dysfunction that can be uncoupled from T cell activation. This distinct dysfunction module is downstream of intracellular metallothioneins that regulate zinc metabolism and can be identified at single-cell resolution. We further identify Gata-3, a zinc-finger transcription factor in the dysfunctional module, as a regulator of dysfunction, and use CRISPR/Cas9 genome editing to show that it drives a dysfunctional phenotype in CD8+ TILs. Our results open novel avenues for targeting dysfunctional T cell states, while leaving activation programs intact. Overall design: CD8 TILs from WT and MTKO mice were sequenced at single-cell resolution