Mesothelin overexpression has been documented in a variety of solid tumors, and CAR T-cells targeting mesothelin have been clinically investigated in mesothelioma, epithelial ovarian cancer, pancreatic ductal adenocarcinoma (PDAC), lung cancers, uterine cancers, triple-negative breast cancer (TNBC), gastric cancer (GC), CRC, esophagus cancer, hepatocellular carcinoma (HCC), as well as neuroendocrine tumors/Merkel cell carcinoma. Here, MSLN is linked to Merkel cell skin cancer.