(A) Historical milestones in cancer research include discoveries, Nobel Prizes, and FDA approvals. (B) Immune checkpoint blockade with anti–CTLA-4 and anti-PD1 antibodies acts via T cells. Upon binding to their ligands, checkpoint receptors expressed on T cells, including PD-1 and CTLA-4, mediate suppression of T cell–mediated tumor killing. Blocking checkpoint receptor signaling using monoclonal antibodies can restore T cell function, leading to successful tumor killing. PFN, perforin; GzmB, granzyme B.