a-b, C57BL/6 J mice were inoculated with 1 × 106 MC38 tumor cells and treated with PD-L1xCD3 (0.25 mg kg−1 on day 10 and 15), 200 μg CTLA4-Ig was administrated on day 10, 13 and 15. Experimental design (a) and tumor growth curve (b) are shown. c-e, CD8 T cells were co-cultured with either tumor cells or dendritic cells in the presence of ErbxCD3. T cell activation (c), apoptotic T cells (d), supernatant IL-2 and IFN-γ (e) were measured by flow cytometry. Data were shown as mean ± s.e.m from a representative experiment of two independent experiments (n = 5 biologically independent animals). Statistical analyses were performed by two-way ANOVA with Dunnett’s multiple comparisons test (b), two-tailed unpaired Student’s t-test (c-e). ***P ≤ 0.001, ****P ≤ 0.0001.