SLAMF9 and COVID-19: By employing a set of signature genes specifically expressed in Slamf9+, Trem2+, Fbp1+, and Marco+Cd36+ macrophages identified in our study (Supplementary Fig. S6d), we confirmed the enrichment of SLAMF9+, TREM2+, FBP1+, and MARCO+CD36+ macrophages and the proliferation of FBP1+ macrophages in the lung autopsy samples of COVID-19 patients (Fig. 5g).