In this study, we estimated the infiltrating immune cells and explored the potential biomarkers in unstable plaques in atherosclerosis patients based on bioinformatics analysis and machine learning, finding that M1 macrophages were an important cause of unstable plaque formation, and CD68, PAM, and IGFBP6 were also diagnostic markers for the early identification of unstable plaques. The gene discussed is IGFBP6; the disease is atherosclerosis.