Regulatory T cells (Tregs, CD4_cluster2) with FOXP3, CTLA4, ICOS, and BATF expression were also abundant, which has been demonstrated as tumor-specific alterations in the tissue microenvironment (Kim et al., 2020; Guo et al., 2018; Gueguen et al., 2021). This evidence concerns the gene ICOS and neoplasm.