STAT3 and cancer: In accordance with this evidence, strategies aimed at depleting Treg cells have resulted in the concomitant restoration of NK cell functionality, including signal transducer and activator of transcription 3 (STAT3) modulation, cytotoxic T-lymphocyte antigen 4 (CTLA-4) inhibition, low oral doses of cyclophosphamide [111], anti-OX40 monoclonal antibody [112], and anti-cancer agents such as Lenalidomide and Pomalidomide [113,114].