CD274 and melanoma: Immune checkpoint blockade antibodies, such as anti‐PD‐1 and anti‐PD‐L1, have exhibited impressive clinical efficacy on many cancer types, but the response rate remains limited and need to be improved.[3] To test whether nanovaccine could improve the therapeutic effect of anti‐PD‐1 treatment in melanoma, we first detected the expression of PD‐1 in the previously mentioned B16‐OVA tumor tissues and observed positive staining of PD‐1, indicating a potential for anti‐PD1 treatment (Figure S9, Supporting Information).