Acquired Resistance to Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICIs) have rapidly altered the treatment landscape for multiple tumor types, providing unprecedented survival in some patients. Despite the characteristic durability of response to ICI, unfortunately many patients with initial response will later develop acquired resistance. The current understanding of mechanisms of acquired resistance to ICIs is remarkably limited, perhaps restraining effective development of next-generation immunotherapies. Here, we examine the barriers to progress and emerging clinical reports interrogating acquired resistance with the goal to facilitate efforts to overcome acquired resistance to ICIs in the future.