CD4 and neoplasm: Red blood cell membrane-coated nanoparticles can protect the antigen from immune system clearance, transfer the antigen in the organs, and directly present the antigen to the immune cells after the treatment of the antigen presenting cells, leading to sensitization and multiplication of antigen-specific CD4 and CD8 effector T cells to induce the immunity reaction to resist neoplasm [57,58,59].