William Coley, MD known as the Father of Cancer Immunotherapy first attempted to harness the immune system for treating cancer in the late XIX century.
Old habits die hard
There is a special place in hell exclusively for members of scientific community (formerly known as Holly Inquisition) their open hostility towards any challenge to the “approved knowledge” reminds me of Galileo, he was prosecuted a century after Magellan’s circumnavigation of the globe.
Another good example, in 1827 Georg Simon Ohm found that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current. This relationship is known as Ohm's law and every high school student can verify it. What was the reaction of contemporary physicists to the discovery? Well, nothing unusual… smear campaign lasted for years.
No wonder why, it took 30 years for Charles Darwin to publish his book. At the time, evolution theory did not comply with the “approved knowledge”.
You might think it was in the past, now things changed. Certainly they have changed, but not for better.