https://atm.amegroups.org/article/view/119609/html

2023 review found most animal tumor-initiation studies did not show nicotine increasing spontaneous tumor initiation, while tumor-progression results were inconsistent and hard to generalize

Smokeless tobacco is not "safe", it's addictive, may have oral/cardiovascular concerns, and long term data is limited, but cancer risk is likely far lower than chewing tobacco. Nicotine alone os not strongly established as cancer causing in humans, but biologically suspicious enough that "harmless" would be too strong.

There's a reason the FDA is allowing Zyn to say there's a difference now with "Using ZYN instead of cigarettes puts you at a lower risk of mouth cancer, heart disease, lung cancer, stroke, emphysema, and chronic bronchitis". People would do better to switch to Zyn than smoke or use dip. They'd do even better quitting, but people should understand there's much higher risk with smoking and using chewing tobacco.

At present, it is not possible to draw a conclusion whether nicotine itself may act as a complete carcinogen.

That study is proposing that nicotine may modify the effect of cancer growth but did not conclude that nicotine itself is a carcinogen.

Get outa here, Joe Camel.

Ehhh... Caffeine isn't nearly as drastic of a vasoconstrictor as nicotine. I would have to read a study about any cardiovascular benefits, but I'm highly dubious and would be willing to bet the benefits do not put weight then negative outcomes.