T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive lymphoid malignancy for which optimal therapeutic approaches for relapsed/refractory disease and biomarkers for upfront risk stratification are currently unknown. Comprehensive, large-cohort bulk-level profiling of T-ALL is currently underway with the promise to reveal novel drivers and associate genetics with treatment response. To synergize with these studies, we designed a single-cell (sc) genomics study powered to comprehensively characterize intra-tumoral arrest states in T-ALL.