Don't forget that the introduction of Smoking laws in most western countries have reduced the 3rd party/passive smoking dramatically.
Anecdotally - As kid visiting offices in the 80s I remember nearly every single adult office worker being a smoker and going into office work places thick with smoke. Vaping does not seem to have the same numbers.
You've got it a bit mixed up Nicotine has not been definitely linked to cancer. Cigarette smoking has, however. But nicotine has been linked to heart disease and related cardiovascular illnesses.