CD274 and neoplasm: Cheng’s team reported a therapeutic peptide assembling nanoparticle that can sequentially respond to dual stimuli in the tumor ECM for tumor-targeted delivery and on-demand release of a short D-peptide antagonist of programmed cell death-ligand 1 (D PPA-1) and an inhibitor of idoleamine 2, 3-dioxygenase (NLG919) [199].