SOCS1 and neoplasm: Our FACS analysis of tumor-infiltrating OT1s found that inactivation of SOCS1 in transferred CD8+ T cells did not affect Slamf6+CD39–PD-1med Texprog cell frequency while enhancing the accumulation of Slamf6–CD39+PD-1hi cells containing Texint, Texeff, and CD8+ T cells (Figure 3D).