Why is commercial law an independent legal department? Can you explain it briefly?

Commercial law is a law to adjust the commercial relationship or commercial behavior between equal subjects. The adjustment object of commercial law is commercial relations. From the form of expression, China's commercial law includes company law, securities law, negotiable instrument law, insurance law, enterprise bankruptcy law, maritime law and so on. Commercial law is a legal department, but many concepts, rules and principles related to civil relations stipulated by civil law are also commonly used in commercial law. In this sense, China implements the principle of "civil and commercial integration". Therefore, China's commercial law is a relatively independent legal department, not a completely independent legal department.