A fucoidan–dextran-based iron oxide magnetic nanosystem was conjugated with an inhibitor (anti-PD-L1) and T-cell activators (anti-CD3 and anti-CD28) to identify and repair the immunosuppressive tumor microenvironment by giving a boost to tumor-infiltrating lymphocytes while targeting the magnetic navigation to the tumors [193]. Here, CD28 is linked to neoplasm.