It has been widely accepted that tumor cells are antigenic, due to the somatic mutations which alter their protein structure/expression profile and being recognized as “foreign” by the immune system. Further, it has long been known that TILs are common among various cancer types and their presence usually correlates to a better prognostic outcome. Given all the evidence, Dr. Steven Rosenberg and his colleagues in the National Cancer Institute ((NCI)) lab first proposed the TIL mediated cancer therapy back in 1986 followed by the first human TIL experiment in metastatic melanoma in 1987. The idea