NRP1 and neoplasm: Treg cells can help tumor cells escape killing by cytotoxic CD8+ T cells, by exerting an immunosuppressive effect [31], and in the context of hepatocellular carcinoma, NRP1 supports Treg cells’ migration behavior, and anti-NRP1 showed a favorable and safe outcome and evoked the antitumor effect of PD-1 blockade [32].