Tobacco is a plant. Cigarettes are a product made from tobacco with many “artificial” chemicals added. Cigarettes are the cause.
Search "benefits of nicotine", yields a wealth of articles supporting this such as: https://pubmed.ncbi.nlm.nih.gov/1859921/
That is full of carcinogens. And nicotine, which IIRC isn't a carcinogen itself but instead promotes tumor growth once they form.
> Cigarettes are the cause.
Chewing tobacco is a great way to get (a different set of kinds of) cancer, too.