Single-cell ATAC sequencing with 10X Genomics profiles chromatin accessibility of individual cells/nuclei, revealing cellular heterogeneity and regulatory processes. The scATAC-seq protocol involves cell isolation, nuclei extraction, transposase reaction for chromatin fragmentation and adapter addition, GEM formation for nuclei encapsulation with unique barcodes, library preparation via PCR amplification, high-throughput sequencing, and data analysis to identify accessible chromatin regions.