Blockade antibodies against T cell checkpoint molecules including CTLA-4 and the PD-1/PD-L1 axis in mono- or combination therapies have begun to revolutionize the current standard cancer treatment in various cancer types, such as melanoma, non-small cell lung cancer (NSCLC), bladder cancer and Hodgkin’s lymphoma [15–22]. The gene discussed is CTLA4; the disease is melanoma.