Q. Does CMOS prefer the use of “persons” or “people” when describing a collection of human beings, such as you might find at a grocery store?
A. More than one person at a grocery store would normally be referred to as people, not persons. According to Garner’s Modern English Usage, the traditional distinction between persons for smaller numbers (especially of specific people) and people for larger numbers (especially of people considered more generally) has fallen out of style in favor of people in most contexts (5th ed. [Oxford, 2022], under “people. A. And persons”).
So one might have once referred to the people at the grocery store but the two persons ahead of me in line. Today, people is usually considered to be the more natural choice for both and can be used just about anywhere the plural is called for.