library_construction_protocol: Isolation, library construction and sequencing of bulk ATAC and RNA were performed at Gene Denovo Biotechnology Co. (Guangzhou, China). For ATAC sequencing, CD4 naive cells from C57 mouse tongue tumors were extracted and the nuclei were extracted. Tn5 transposase was added to the nuclear suspension for transposition reaction. After the reaction was completed, the DNA fragment was purified; the amplified product was then used for PCR amplification. The fragments were purified using AMPure XP magnetic beads (Beckman Coulter, Brea, CA, USA) to construct a sequencing library. After the library construction was completed, Agilent 2100 (Agilent, Santa Clara, CA) was used to detect the quality of the library. Libraries that pass the quality inspection will be used for on-machine sequencing (Novaseq 6000) to obtain sequence information of the open chromatin region fragments to be tested. Extraction of CD4 naive cells from C57 mouse tongue tumors . Total RNA was extracted using Trizol reagent kit (Invitrogen) according to the manufacturer's protocol. RNA quality was assessed on an Agilent 2100 Bioanalyzer (Agilent Technologies) and checked using RNase free agarose gel electrophoresis. After total RNA was extracted, eukaryotic mRNA was enriched by Oligo(dT) beads (Prokaryotic: After total RNA was extracted, prokaryotic mRNA was enriched by removing rRNA by Ribo-ZeroTM Magnetic Kit (Epicentre).Then the enriched mRNA was fragmented into short fragments using fragmentation buffer and reversely transcribed into cDNA by using NEBNext Ultra RNA Library Prep Kit for Illumina (NEB #7530, New England Biolabs).The purified double-stranded cDNA fragments were end repaired, A base added, and ligated to Illumina sequencing adapters. The ligation reaction was purified with the AMPure XP Beads (1.0X). And polymerase chain reaction (PCR) amplified. The resulting cDNA library was sequenced using Illumina Novaseq6000 by Gene Denovo Biotechnology Co. (Guangzhou, China)