Capability Maturity Model Integration (CMMI) is a process improvement approach that provides organizations with the essential elements of effective processes. It has five levels of process maturity: initial, managed, defined, quantitatively managed, and optimizing. As organizations advance through these levels, their processes become more predictable, measurable, and controlled. CMMI helps organizations improve quality, productivity, customer satisfaction, and return on investment. Large companies like Boeing, Tata Consultancy Services, and Accenture have achieved high levels of CMMI and realized significant benefits like increased productivity and reduced defects.