My understanding is that immunotherapy has been shown to work great for cancers without solid tumors and results have been disappointing with solid tumors. It isn't that it's marching steadily forward and will eventually have been shown successfully everywhere.
I think people running down John Horgan's editorial keep citing successes -- multiple myeloma! cured! -- but aren't addressing his overarching argument, which, as I understand it, is that people are being sold false hope in the majority of cases -- familiar cancers like breast cancer, lung cancer, prostate cancer, colo-rectal cancer -- which has the negative consequences of impoverishing them and increasing their suffering for negligible benefit.
To be clear, I don't have any horse in this race aside from insurance bills.