Ipilimumab is a CTLA4 neutralizing antibody approved as a monotherapy for advanced melanoma, whereas a second CTLA4 antagonist, Tremelimumab, is approved for combination use with other checkpoint inhibitors in cases of liver cancer (de Castria et al., 2022; Hargadon et al., 2018; Korman et al., 2022). Here, CTLA4 is linked to liver cancer.