Is income from a sole proprietorship that holds rental real estate eligible for the 20%qualified business income deduction?

The qualified business income deduction applies only to a trade or business. Under an IRS-created safe harbor, a rental real estate activity may be treated as a trade or business for purposes of this deduction. Details of this safe harbor are in IRS Revenue Procedure 2019-38 (https://www.irs.gov/pub/irs-drop/rp-19-38.pdf).