(a) Bio-nanoconjugates consist of nanoparticles physically tethered to targeting agents, which may be antibodies, aptamers, peptides, or small molecules. (b) Biomimetic nanoparticles consist of nanoparticles coated with natural cellular structures to prevent immune recognition, prolong circulation, and enhance tumor delivery. The two types of biomimetic nanoparticles are (i) nanoparticles that present specific cell constituents, and (ii) nanoparticles that are completely disguised by entire cell membranes or loaded within whole cells.