Does the human body have the capability to heal itself? The idea of immunotherapy, harnessing the body’s own immune system to eradicate disease, has moved from the realm of possibility to something much more tangible. Interestingly, this promising therapy is not a new concept and has actually existed for more than 125 years, originating when William Coley, MD introduced the notion that the immune system could be useful in the treatment of cancer. He had observed that bone and soft tissue sarcoma patients experienced remission as a result of a concurrent bacterial infection and began to treat patients with heat-killed streptococcal organisms that he called Coley toxins. The toxins he administered to patients resulted in a 50% near-complete remission rate (Institute for Clinical Immuno-Oncology 2015).