SPP1 and cancer: TAM is abundant in many solid tumors and has generally been associated with negative outcomes,[16, 17] therapeutic resistance[18, 19], and tumor invasion.[20] Yet, macrophages are plastic, and different phenotypes have been identified by single‐cell RNAseq.[2] Notably, a recent study[1] identified TAM‐associated SPP1 expression as a key negative predictor of patient clinical outcomes in various cancer types (Figure1A,B).