Cell‐penetrating peptides (CPPs) became one of the most powerful tools in the field of molecular delivery. Since their discovery, more than 20 years ago, the number of CPPs increased considerably (see CPP site 2.0, a database of CPPs, http://crdd.osdd.net/raghava/cppsite/). CPPs can facilitate the intracellular delivery of numerous molecular cargoes such as drugs, imaging and radiotherapeutic agents, proteins, nucleotides, DNA, gold nanoparticles, and even liposomes, or magnetic nanoparticles in a nontoxic manner. In the past two decades, hundreds of CPPs have been developed and described by scientific studies, including pVEC, TP10, TP10‐2, SynB3, and Tat 47–57.