“delta 9-Tetrahydrocannabinol (delta 9-THC) was studied for potential carcinogenicity in rodents because it is the principal psychoactive ingredient in marihuana and it has potential medicinal uses.

There was no evidence that delta 9-THC was carcinogenic in rats or mice.”

https://pubmed.ncbi.nlm.nih.gov/8812248

https://www.sciencedirect.com/science/article/abs/pii/S0272059096900482?via%3Dihub