I had a very good friend and high school alumni who was diagnosed with very treatable lung cancer. He got hooked by a “snake oil” salesman and very expensive but worthless “treatment”. Sadly, he passed, quickly. By the time he embraced science-based medicine, it was too late.
I don’t know if marijuana is a lung cancer remedy. There have been no trials, no scientific research, and consequently no data. The import of science-based treatment is that results are repeatable.
Immunotherapy is new. I wouldn’t do anything that might affect its treatment impact. It has dramatically moved the survival needle. Don’t introduce something that may compromise your best chance at survival.
Stay the course.