Pre-clinical studies have shown that anti-4-1BB when used in combination with anti-OX40 is more effective at boosting CD8 T-cell expansion, effector function, and anti-tumor immunity (Adler and Vella, 2013; Lee et al., 2004; Morales-Kastresana et al., 2013). This evidence concerns the gene TNFRSF9 and neoplasm.