CD274 and neoplasm: M1 mitochondria, extracted from inflammatory M1 macrophages, are engineered with mannosylated polyethyleneimine (mPEI/M1mt) to metabolically repolarize the immunophenotype of M2 tumor‐associated macrophages, acquiring an immune‐supportive tumor microenvironment (TME) and enhancing tumor anti‐PD‐L1 therapy.