Ex vivo gene therapy refers to a type of gene therapy that involves the transfer of well-functioning genes into the cells or tissues outside the body before returning them to the patient's body. Additionally, it is also called cell-based gene therapy. Various terms are used interchangeably to describe ex vivo gene therapy, such as in vitro gene therapy, cell therapy, cell transplantation, or cell-based therapy. These terms convey different notions and refer to the same treatment approach that aims to restore normal cell function by introducing modified genetic material. Regardless of the nomenclature, ex vivo gene therapy remains a promising therapy that has the potential to revolutionize the treatment of genetic disorders.