The Audit Department reports to the Chairman and the Audit Committee in business and to the President in administration.
As you said, it is the internal audit of listed companies, so it still serves the company, not the country or even state-owned enterprises. Having one-vote veto is a compulsory measure, which has not been realized so far. But some businesses need the approval of the company's audit department. This is feasible, and then the management will make the final decision based on the trust in the auditor.
Financial and basic system audit is a part of internal audit. In fact, when a company's internal control system is perfect, the basic system audit is not the focus of work, and so is the financial audit.
In enterprises, internal audit is different from other departments. It looks at how the enterprise is doing from the perspective of outsiders, which is its independence. However, it truthfully reported the results it saw to the company's top management, and at the same time called for its own analysis and some directional suggestions. At this time, it is also a part of the enterprise because its independence does not include the board of directors. This independence is the biggest difference from the external audit, because the external audit is also a suggestion and an audit, but after all, they are outsiders and can't be so dedicated.