The accumulating evidence for tumor neoantigens as critical target antigens for tumor rejection coupled with the striking correlation of anti-CTLA-4 and anti-PD-1 induced tumor responses with the mutational/neoantigen load in NSCLC, melanoma, and microsatellite instability (MSI) high tumors make a strong case for vaccination targeting neoantigens [7–9, 13, 14]. Here, CTLA4 is linked to melanoma.