Genomic engineering in cell lines is a versatile tool for studying gene function, designing diseases models, biopharmaceutical research, drug discovery and many other applications. CRISPR (Clustered Regulatory Interspaced Short Palindromic Repeats)/Cas9 systems is a newly developed yet the most popular method for genome editing. It has been widely used in current biology, functional genome screening, cell-based human hereditary disease modeling, epigenomic studies and visualization of cellular processes.