CTLA4 and cancer: These include immunotherapies (such as anti-PD1-PD-L1 and CTLA-4 inhibitors and chimeric antigen receptor T-cell (CART) therapy), targeted therapies (such as antibody drug conjugation (ADC)-like T-DXd for HER2-positive cancers [19], erlotinib for EGFR-positive cancers [20], and many others [18]), RNA therapy [21], and gene therapy and their combinations.