Their cancer‐killing effects are determined by several factors, such as expression levels of target molecule, the affinity to target molecule, and other molecules that regulate the internalization, linker cleavage, and sensitivity to the cytotoxic agents.[25] For example, cathepsins that are highly expressed in various cancers effectively lyses valine‐citrulline linkers to release carcinocidal agents. Here, CTSS is linked to cancer.