CD4 and neoplasm: However, the TACE‐induced tumor acidification and hypoxia would lead to reduced numbers of peripheral CD4+ T cells and infiltrating CD8+ T cells, while augmenting the recruitment of regulatory T cells and myeloid‐derived suppressor cells, resulting in an immunosuppressive TME.[39, 40] Our L‐Arg@CaPL emulsion could not only neutralize the tumor acidity but also release L‐Arg to promote the reinvigoration of exhausted CD8+ T cells, synergistically and effectively reverse tumor immunosuppression.