CTLA4 and neoplasm: Further analyses revealed that CM patients in Cluster 2 not only had more immune cell infiltrates (e.g., CD8+ T and B), higher immune infiltration score, and more active immune function (e.g., Inflammatory promotion) but also displayed a higher immune checkpoint activity, such as CTLA4, CD274 (PD-L1), HAVCR2 (TIME3), and LAG3. Hence, the CM patients in cluster 2 had most of the characteristics of a hot tumor and might respond better to immunotherapy.