STAT3 and B-cell chronic lymphocytic leukemia: showed that IL‐10R/STAT3 pathway correlated with the accumulation of a PD‐1int CD8+ T‐cell subset, which plays an important role in tumor elimination, and the loss of IL‐10R/STAT3 signaling enhanced the accumulation of functionally impaired PD‐1hi CD8+ T‐cells associated with the progression of tumors in a chronic lymphocytic leukemia model.149