Powerful imaging agents and a theranostic concept targeting CXCR4 have evolved during the last decade, and their increasing clinical impact is reflected by an eleven-fold increase in the number of publications per year (PubMed search for “CXCR4 imaging PET cancer”) during the last decade (2011–2020) and highlighted in several comprehensive reviews [1,2,3,4]. Here, CXCR4 is linked to cancer.