I also have cancer of unknown primary and was diagnosed 2.5 years ago. Currently I am undergoing treatment with immunotherapy and chemotherapy and it is keeping the cancer stable. It has been a rollercoaster that's for sure, but the side effects are minimal and I am able to continue working (although I am looking seriously at retirement). @tobydrake7, I have no idea if my particular treatment is an option (OPDIVO + FOLFOX) but so far so good. I wish you peace!