SPP1 and cancer: Previous studies have indicated that the Mφ promote cancer initiation and malignant progression, and are more correlated with LUSC than LUAD.12,49 In this study, we found that some chemokine-related molecules, including CXCL2, CCL3, and CCL3L1, were concentrated in states 1, 3, and 5, which enriched SPP1-Mφ and were basically a half-half mixture of LUAD and LUSC at branch 1 (Fig. 6c, d and Supplementary Fig. 7b).