Considering the upregulated PD-L1 expression of tumor cells after treatment with the in situ gel vaccine and intrinsically high PD-1 expression of tumor-infiltrating CD8+ T cells, we next studied whether the antitumor efficacy of the gel vaccines could be further improved via combination with anti-PD-1 checkpoint blockade therapy (Fig. 6c). This evidence concerns the gene CD274 and neoplasm.