STAT5B and cancer: To investigate the potential relationship between IL-7–IL-7R signaling and CD8αβ+ γδ T cells in the context of cancer, we used transgenic mice expressing a frequent human (h) oncogenic driver mutation in the IL-7R effector and key signal transducer STAT5B, Asp642His (N642H), which is associated with poor prognosis and increased risk of relapse31.