Compared with PBS and PEG(0) NP, PEGylated NPs as well as the soluble vaccine group upregulated CD86 and downregulated CD206 on macrophages in TDLNs (Figure 5I,J), resulting in a decreased ratio of M2/M1‐like macrophages (Figure 5K).[18] We observed similar activation of DCs and macrophages in tumor‐draining axillary LNs, but not in contralateral non‐tumor‐draining inguinal or axillary LNs (Figures S8 and S9, Supporting Information). Here, MRC1 is linked to neoplasm.