James Patrick Allison (born August 7, 1948)[4] is an American immunologist and Nobel laureate who holds the position of professor and chair of immunology and executive director of immunotherapy platform at the MD Anderson Cancer Center in Houston, Texas.

[12][13] Allison earned a Bachelor of Science degree in microbiology from University of Texas, Austin, in 1969, where he was a member of Delta Kappa Epsilon fraternity.

He earned his doctor of philosophy degree in biological science in 1973, also from UT Austin, as a student of G. Barrie Kitto.

He was a professor of Weill Cornell Medicine and co-chair of the Department of Graduate Program in Immunology and Microbial Pathogenesis at Weill Cornell Graduate School of Medical Sciences from 2004 to 2012, and also a Howard Hughes Medical Institute (HHMI) investigator until 2012, when he left to join the MD Anderson Cancer Center in 2012.

Allison trained at Scripps Research under tumor-immunologist Ralph Reisfeld, Ph.D., professor emeritus, researching human leukocyte antigens (HLA) and T-cells and exploring the role HLA proteins play in enabling the immune system to distinguish self from invaders.

In 1977, Allison and a colleague, G. N. Callahan, reported in a letter to Nature that they had found evidence that the immune system was prevented from attacking cancer cells due to antigens’ association with additional proteins.

In 1996, Allison was the first to show that antibody blockade of a T-cell inhibitory molecule (known as CTLA-4) could lead to enhanced anti-tumor immune responses and tumor rejection.

This concept of blocking T-cell inhibitory pathways as a way of unleashing anti-tumor immune responses and eliciting clinical benefit laid the foundation for the development of other drugs that target T-cell inhibitory pathways, which have been labeled as "immune checkpoint therapies".

[12] This work ultimately led to the clinical development of ipilimumab (Yervoy), which was approved in 2011 by the FDA for the treatment of metastatic melanoma.

Once defined, the basic studies are used to develop new strategies for the treatment of autoimmune diseases and immunotherapy of cancer.

[37] He, along with Tasuku Honjo, was jointly awarded the Nobel Prize in Physiology or Medicine in 2018 for their discovery of cancer therapy by inhibition of negative immune regulation.