In assessing the impact of SOCS1 and PD-1 inactivation in transferred CD8+ T cells on the cellular composition of tumor, we observed depletion of Foxp3+ Tregs relative to sgOlf OT1s in mice treated with sgSocs1 OT1s, but not sgPD-1 OT1–treated animals. The gene discussed is SOCS1; the disease is neoplasm.