I wouldn't count the Known to the State of California warnings for much. They added that warning to coffee cups despite the link being weak and contrived.

And as others said, no study has linked consumption of weed edibles (or weed vaping) to causing cancer. In fact, it's the opposite. Several (preliminary) studies show that marijuana retards of reduces the risk of some cancers. It is often prescribed to cancer patients for appetite-gain and pain reduction (with fewer side-effects than other prescriptions for the same), but is also now being prescribed for its potential anti-carcinogenic properties.