T-cell checkpoint inhibitors, such as drugs targeting PD-1/PD-L1 and CTLA-4, have been successful at helping the immune system attack certain tumors, but the drugs fail to spur a response in many tumor types. Palleon Pharmaceuticals Inc. is taking a different approach, developing drugs to inhibit glycoimmune checkpoints that allow tumors to evade the innate immune system – dendritic cells, macrophages and NK cells – as well as T cells.