CXCR6 and neoplasm: The observation that Trm cells resembled more of the effector/effector memory than the central memory phenotype is in agreement with previous observations.17 37 38 Comparison of OT1 CD8+ T cells prior to transfer (top), 7 days post-transfer in recipient blood (middle) and in endpoint tumors (lower) revealed again that CXCR6 is acquired by T cells only in tumors and marks CD44+CD62L−CD103+ tumor-resident memory cells, but not circulatory cells (online supplemental figure 3B).