It actually doesn't matter who's in power. The IRS isn't going to open an audit on a sitting president. Period.doubtful one will be opened as long as there are enough Democrats to keep it from happening.
The last time something remotely similar to that happened was when Bush the elder got elected. His tax return had already been randomly selected and was in the process of classification to determine if it would be audited. Technically, it was under audit but no work had been done. That's normal and lots of audits run the same way - the return is pulled, an experienced agent gives it a quick once-over to see if there's anything worth auditing, and most of the time those returns get sent right back to files without the taxpayer ever knowing anyone pulled their tax return.
Of course, in the Bush case, the Secret Service dispatched two Special Agents to pull it from the process. They literally stood over the return all the way through the process of it being taken out of audit status. At every step, they warned every person who had to touch the paper that if they so much as turned the front page of the return and tried to read anything on it, they would be immediately arrested. When the return was processed, they "volunteered" to act as couriers to take it back to files. The tax return left the Houston office with them, ostensibly to be taken to Austin for filing.