Seattle is one of the world’s centers of cancer immunotherapy. Three years ago, Xconomy gathered some of the field’s experts to talk about the promises of harnessing the immune system to fight cancer. Today, some of those promises seem well within reach, and a small but growing number of patients are benefiting from a handful of approved (and expensive) drugs. But while the opportunities seem closer at hand, many challenges remain. It’s time to gather again in Seattle to discuss what’s gone right, what’s gone wrong, and how the field’s brightest minds are working through the obstacles inherent when complicated biology, cutting-edge medical practice, and financial pressures meet.