Hi Mary, I was on Opdivo by itself for 14 months, and then in combination with a trial drug for another 13 months after that. For me, and many others who I've spoken with who have also been on it, the side effects of Opdivo by itself were very mild when compared to other drug treatments I've taken through this lung cancer experience. As with any drug, quite a few side effects are "possible", some could even be serious, as you note, but I think it is safe to say that this has certainly been the exception rather than the rule.
When making decisions about which potential therapy to use, it is important to consider the side effects, but not to get wrapped up in the one or two bad reviews "if" there are many countering views on the treatment to offset that.
Like all lung cancer treatments, Opdivo is not a panacea and will not work well for all patients, but for those patients who are the right fit for it, well, it can have very good results, often for significant lengths of time. Also, if you haven't already done so, perhaps you would want to ask your doctor about Keytruda or Tecentriq if he/she wants you to go the immunotherapy route. Just my personal opinion.