To address the question of whether the upregulated CTLA4 in tumor tissues was originated from the increased immune infiltration, especially the infiltration of CTLA4 abundant CD4+ T cells, we estimated the abundances of six immune cell types (B cells, CD4+ T cells, CD8+ T cells, macrophages, neutrophils, and dendritic cells) in tumor and paired adjacent tissues by re−analyzing gene expression data using TIMER web tool (Supplementary Figure S1). Here, CD8A is linked to neoplasm.