I can't see why marijuana/cannabis would interact negatively with TKI's - at least no more than alcohol - although the liver is rather stressed when processing alcohol and pharmaceuticals in general, but if you are smoking- pref vaping- the liver will be bypassed. Other things - herbs like St John's Wort (hypericum), grapefruit juice, ibuprofen (Neurofen) to name but 3, have been shown to interact negatively with TKIs/Glivec.
If you want to continue to ingest cannabis, you could reassure yourself by keeping an eye on your PCR ratio over the longer term, if there is no change then you could carry on without too much worry.
Remember, smoking tobacco is definitely not good for your health so maybe find another way (vaping? although there are chemicals involved) or preferably smoke without tobacco?
Sandy