TGFB1 and neoplasm: The PLGA‐b‐PEG NP system was co‐encapsulated with a transforming growth factor‐β (TGF‐β) inhibitor, resiquimod (R848), to stimulate the proliferation of tumor‐infiltrating CD8+ T cells, or with SD‐208, to sustain the release of the drug in systemic circulation.