PROJECT ABSTRACT This revised application seeks renewal for years 36-40 of a T32 program that will provide training for 7 postdoctoral MD, PhD or MD/PhD scientists. The training program is centered in the Department of Pathology and Immunology (P&I) at Washington University in St. Louis, and consists of 36 training mentors who are housed in 10 different departments. The training faculty consists of 16 women and 20 men and includes 2 URM. The faculty are a highly interactive group of immunologists with interests in cancer immunology and cell/molecular cancer biology and are led by a director and associate director who are well known for their contributions to cancer immunology/immunotherapy and their commitment to training of young scientists. The research of our faculty focuses on various aspects of cancer immunology and immunotherapy with an emphasis on the molecular basis of cellular activation and suppression. A Steering Committee of six T32 faculty members oversees the training program and is responsible for the selection and oversight of the trainees. We also formed a new external advisory board to obtain outside opinions on our T32 program. Training includes a 2-to 3-year period of full- time laboratory research, where the trainee is exposed to the latest approaches in cancer immunology and cell and molecular cancer biology. The training also includes presenting at laboratory meetings, participation in weekly seminars and yearly retreats, training in research ethics and rigor and reproducibility, participation in national/international meetings and opportunities to audit advanced courses in Immunology, Cell Biology and Cancer Biology. During the most recent 10-year funding period of this T32, 49 trainees were supported by the Program: 4 withdrew for personal reasons and 7 trainees who had just started the program had their work delayed by the COVID-19 pandemic. The remaining 38 trainees published 171 papers with 33 papers appearing in high impact journals and 76% of these trainees had at least one first-author paper. Of the 70 trainees who have been or are supported by this Program in the last 15 years, 66 (94%) have remained in research. These demographics document the success of our T32 Training Program and provide strong support for its competitive renewal.