Molecular changes in immune cells associated with disease conditions have not been analyzed in depth. It is obvious that our immune system plays a critical role in various biological and pathological conditions, such as infection, autoimmune diseases, drug-induced skin and liver toxicities, food allergy and rejection of transplanted organs. The recent development of cancer immunotherapies clearly demonstrates the importance of host immune cells, particularly drugs modulating the immune checkpoint molecules, in the fight against cancer. However, the molecular mechanisms by which these new therapies kill tumor cells still remain unclear. In this regard, Dr. Yusuke Nakamura has begun to explore the role of newly-developed tools, such as next generation sequencing, in the genetic characterization of the immune system. This new field, which has been referred to as immunogenomics/ immunopharmacogenomics. has enormous potential to help us better understand the changes/alterations to our immune responses during the course of various disease conditions and to use this knowledge to personalize therapeutics for our patients.