For ICIs, one antibody targeting Cytotoxic T Lymphocyte-Associated Protein 4 (CTLA-4), six anti-programmed cell death 1 (anti-PD1) and anti-programmed cell death 1 ligand 1 (anti-PD-L1) antibodies have been approved by the US Food and Drug Administration (FDA) against over 15 different types of malignancies [1]. Here, CTLA4 is linked to cancer.