PTPN2/1-IN-4 (Compound WS35) is an orally active dual inhibitor of PTPN1 and PTPN2, with IC50 values of 12.8 nM and 5.8 nM, respectively. It modulates the IFNγ-JAK-STAT signaling pathway and significantly enhances CD8+ T cell tumor infiltration. PTPN2/1-IN-4 demonstrates potent anticancer activity, effectively inhibiting tumor growth in the B16-OVA syngeneic mouse model both as a monotherapy and in combination with anti-PD-1 antibody treatment.