Rationale: STAT3 inhibition suppresses Tregs; Synergizes with anti-CD19 CAR-T in lymphoma; Causal proof via JAK3 inhibition (reverses CAR-T STAT3 activation). Challenge: Paradoxical STAT3 activation in CAR-T cells; rapid renal clearance limits systemic exposure. The gene discussed is STAT3; the disease is lymphoma.