For example, this review focuses on whether the cytokine release syndrome (CRS) observed in human cancer patients treated with a 41BB or CD40 agonist antibody was likely a consequence of the underlying structural features of those antibody therapeutics rather than a deep dive into the specific differences in 41BB mediated costimulation of CD8 positive T cells versus CD40 mediated costimulation of antigen presenting cells (6–8). Here, CD40 is linked to cancer.