Several cancer types showed a high level of TIGIT on the tumor-infiltrating lymphocytes (TILs) (182). TIGIT recognizes the poliovirus receptor (PVR), also known as CD155 or Necl5, as well as the Nectin-2 (CD112), or Nectin-3 ligands that are overexpressed on multiple cancer types (183–185) and linked to unfavorable prognosis in several cancers (186, 187). Here, PVR is linked to cancer.