For the moment, approved immunotherapies include the oncolytic virus talimogene laherparepvec for melanoma [103], the dendritic vaccine Sipuleucel-T for prostate cancer [104], two CD19 targeting CAR-T cells for acute lymphoblastic leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL) [105], and seven checkpoint inhibitors targeting either the PD1/PD-L1 or CTLA-4/B7-1/B7-2 axis (reviewed in [106]). Here, CTLA4 is linked to acute lymphoblastic leukemia.