Usually the big advances are built on a number of small incremental advances. Think about modern immunotherapy like CAR-T. Rather than recap myself I'm just going to post this timeline of the milestones that led to CAR-T over many decades: https://www.mskcc.org/timeline/car-t-timeline-progress.

You'll generally be disappointed, though. "Cancer" isn't really a thing. It is a family of disorders characterized by several properties that arises from different causes. At this point in my life, I am very confident that we will never have a single general cure for cancer (killing mutated cells, repairing carcinogenic dna damage).