For those interested in some of the history of immunotherapy, and cancer treatments more generally, I recommend Dr Peter Attia's excellent interview[1] with Dr Steven Rosenberg. Dr Rosenberg is Chief of Surgery at the National Cancer Institute, and was on the ground floor and helped pioneer the use of immunotherapy in fighting cancer[2].
[1] - https://www.youtube.com/watch?v=pVMl0LgdnOU [2] - https://en.wikipedia.org/wiki/Steven_Rosenberg