The Qualified Business Income Deduction was enacted in the Tax Cuts and Jobs Act of 2017 which went into effect on 1 Jan 2018.
If you earn income from qualified business (only applies to defined pass-through businesses - such as LLCs, S corporations, partnerships and sole proprietorships), and that business has a taxable income below $157.5K (singles) or $315K (married filing jointly) then you qualify for an additional deduction of 20%.
There is a somewhat complex phase-out of the the deduction above these levels, using the W-2 Limit. There are quite different outcomes for a Sole Proprietor (including single member LLCs), S-Corp (with wages paid) and Partnerships (including multiple member LLCs). there are further differences if the business a "specified trade or business" or a "non-specified trade or business". Specified business include accounting, brokerage services, consulting, financial services health and law services.
In your example, which is below the thresholds, it's 20% of $180K or an additional $36K worth of deductions, reducing your business income to $144K. At 24% tax rate, this is effectively worth $8.64K to you.
This is designed to assist small business owners and help them expand their business by employing more people, but can of course go into your own pocket if you desire.
It's also clear that this Tax Act introduces some quite significant choices for the choice of which business entity to use when the income exceeds the thresholds (157.5K singles, 315K joint).
Disclaimer: This an opinion only. You should seek professional advice for tax matters, especially for a business, given the changing landscape of tax matters in general.