 Immune Cell Abundance Identifier, MSLAI, is a gene-set signature-based method that accurately estimates the abundance of 24 immune cell types, including 18 T-cells subsets, from gene expression data. MSLAI outperforms other methods in estimating immune cells, particularly T-cells subsets, and can predict immunotherapy response with high accuracy. This article was authored by Yerou Miao, Zhang Zhang, Qian Lei, and others.