STAT3 and cancer: Intriguingly, our previous work and that of others have identified signal transducer and activator of transcription 3 (STAT3) as a key factor driving the pro-tumoral (N2) phenotype in neutrophils with deficient type I IFN signaling.11,17 STAT3 is a well-established oncogenic transcription factor that is aberrantly activated in many human cancers, where it drives tumor cell proliferation, survival, angiogenesis, and immune evasion.24 Beyond its intrinsic tumor cell effects, STAT3 signaling plays a critical role in shaping the immune microenvironment.