a Flow cytometry assay of dendritic cell maturation in the lymph nodes after treatments with PBS, aPD-1, VNP@Gel, GD/EI-NP@Gel, VNP-GD@Gel, VNP-GD/EI-NP@Gel and VNP-GD/EI-NP@Gel+aPD-1 (n = 4 mice). b Flow cytometry assay of CD8+ T cell infiltration in the tumor tissue after treatments as mentioned above, n = 4 mice. c Dendritic cell maturation in the lymph nodes after different treatments. Data are shown as mean ± s.d. and analyzed with one way ANOVA followed by Tukey’s multiple comparisons test, n = 4 mice (VNP-GD@Gel vs. VNP-GD/EI-NP@Gel: ***P = 0.0008; VNP-GD@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: ***P = 0.0002; VNP-GD/EI-NP@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: nsP = 0.4116). d The number of CD8+ T cells per mg tumor tissue after different treatments. Data are shown as mean ± s.d. and analyzed with one way ANOVA followed by Tukey’s multiple comparisons test, n = 4 mice (VNP-GD@Gel vs. VNP-GD/EI-NP@Gel: *P = 0.0215; VNP-GD@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: ****P < 0.0001; VNP-GD/EI-NP@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: **P = 0.0042). e The number of Granzyme B+CD8+ T cells per mg tumor tissue after different treatments, n = 4 mice (VNP-GD@Gel vs. VNP-GD/EI-NP@Gel: **P = 0.0065 VNP-GD@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: ****P < 0.0001; VNP-GD/EI-NP@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: **P = 0.0028). HMGB1 (f), IFNγ (g), and TNFα (h) expressions in the tumor tissues after different treatments detected by ELISA. Data are shown as mean ± s.d. and analyzed with one way ANOVA followed by Tukey’s multiple comparisons test, n = 4 mice. (f, VNP-GD@Gel vs. VNP-GD/EI-NP@Gel: **P = 0.0080; VNP-GD@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: **P = 0.0017; VNP-GD/EI-NP@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: nsP = 0.5319. g, VNP-GD@Gel vs. VNP-GD/EI-NP@Gel: *P = 0.0256; VNP-GD@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: ***P = 0.0002; VNP-GD/EI-NP@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: *P = 0.0127. h, VNP-GD@Gel vs. VNP-GD/EI-NP@Gel: **P = 0.0047; VNP-GD@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: ****P < 0.0001; VNP-GD/EI-NP@Gel vs. VNP-GD/EI-NP@Gel+aPD-1: **P = 0.0053.) i Luminex-based quantification of cytokines and chemokines, including IL-1α, IFN-γ, TNF-α, MCP-1, IL-12, IL-1β, IL-6, IL-27, IL-17A, GM-CSF (n = 5 mice). Source data are provided as a Source Data file.