Two approximately 2 million year-old fossilized bones had cancerous tumors, shedding light on how long cancer has existed. Current theories believes that cancers first appeared in modern human societies because of longer human life spans and artificial chemicals have spurred the increased prevalence of cancers. But with this new observation, new theories arise.

Source: https://www.sciencenews.org/article/oldest-evidence-cancer-human-family-tree-found?tgt=nr