Checkpoint blockade can trigger the first wave of tumor rejection even when a key dendritic cell subset (cDC1) is missing, according to a study from Hokkaido University and collaborators. The finding refines expectations for early response biology under immune checkpoint inhibition, but also indicates that durable immune memory may not form in the same setting. The work reinforces that immunotherapy response is not only about tumor rejection signals but also about whether immune systems leave lasting protection. For translational planning, the cDC1 dependency becomes a mechanistic filter for interpreting response durability across patient populations.