As a third party, the auditor's job is financial review. Simply put, you can't talk nonsense about how much money you made this year, how much cost you have, and other financial indicators. You need an auditor to verify whether your bookkeeping conforms to accounting standards, whether there is fraud, etc ... Only in this way can you issue an audit report and determine the final financial results.
The scope of financial consultation is much wider, and all financial-related consulting projects can be counted as financial consultation. According to customers' requirements, there are financial system design, cost control and accounting standards ... In short, when the company encounters any problems it can't/doesn't want to do, it will ask for advice. ...
Of course, there is still a close relationship between the two departments. No matter from the contact between employees or from the business. For example, during my internship in financial consulting, my colleagues in the project turned to colleagues in the audit department without knowing whether a certain practice was in compliance, and some employees in financial consulting were transferred from auditing. There are often consulting par and auditing par to introduce each other's business and so on.