CTLA4 and neoplasm: The following section summarizes the available knowledge on tumor-associated ICPs (i.e., PD-L1/PD-1, CTLA-4, B7-H3, B7-H4, CD155, CD200, VISTA, TIGIT, CD47, CD70-CD27, CEACAMs and galectins) that have been shown to be involved in mediating CSC immune evasion, with a focus on recently discovered ICPs (Table 2).