Moreover, IM cells and their two predominant subtypes in murine lungs were clearly distinguished by scRNA-seq. Furthermore, we performed flow cytometry to verify the increase of Trem2hi IMs in PCP and performed immunofluorescence to confirm the co-expression of Trem2 and MerTK, which strengthen the reliability of our transcriptional data for immune cells during PCP. Here, MERTK is linked to pneumocystosis.