This month’s paper features the results of a Phase I study on a new cancer immunotherapy drug. VTX-2337 is a toll-like receptor 8 agonist, activating a part of the innate immune system to stimulate a response that promotes anti-tumor activity. Here, biomarker data is shown that supports activation of the TLR8 pathway and the authors state that future research will use these targets to measure activity when the drug is combined with other agents to modulate TLR8. This research demonstrates an important role for biomarkers in the promising new field of cancer immunotherapy.