Tumor tissue were freshly collected by homogenization, enzyme digestion, and filtering. Viable tumor cells were purified by debris removal, dead cell and mouse cell removal. Suspended single cells were used for scATACseq on the 10X Genomics platform, Chromium Next GEM Single Cell ATAC v2 kit. Single-cell ATAC libraries were prepared according to the manual from 10XGenomics Chromium Next GEM Single Cell ATAC v2 kit.