Indeed, it has been reported that CTSB+ TAMs play a vital role in promoting cancer metastasis and chemoresistance.[38] Moreover, CTSB has been shown to be a negative prognostic biomarker and therapeutic target for some cancers, such as gliomas, hepatocellular carcinoma, and lung squamous cell carcinoma.[34, 39, 40] In the present study, we found that CTSB was a negative prognostic biomarker for LUAD. Here, CTSB is linked to central nervous system cancer.