(UroToday.com) The International Kidney Cancer Symposium 2021 annual hybrid meeting included a Keynote Address by 2018 Nobel Prize laureate Dr. James Allison who discussed immune checkpoint blockade in cancer therapy. Dr. Allison started his talk by noting that in 1996, based on data regarding signals that regulate T cell responses, Dr. Allison hypothesized that tumor cells, which do not express B7 molecules, have a head start against the immune system given that T cells can not initially recognize tumor cells. However, as tumors grow and a few tumor cells died, antigen presenting cells are able to phagocytose the dead tumor cells and present mutated tumor antigens via MHC to T cells. Subsequently, T cells would interact with antigen presenting cells, in the context of T cell receptor plus MHC plus antigen and CD28 plus B7. This would subsequently lead to T cell activation consisting of proliferation and cytokine production, and lead to activated T cells focused on tumor eradication, as summarized in the following figure: