CD47 and cancer: CaCO3 nanoparticles can gradually dissolve and release the encapsulated aCD47 in the acidic and inflamed tumor microenvironment, thus promoting the activation of M1-type tumor-associated macrophages (TAMs), inducing macrophage phagocytosis of cancer cells via blockade of the CD47 and signal regulatory protein-α (SIRPα) interaction as well as boosting antitumor T cell responses.