The threshold they are referring to is the Alice/Mayo test.
https://crsreports.congress.gov/product/pdf/IF/IF12563
> The Supreme Court decisions referenced above established what has come to be known as the two-step Alice/Mayo test for patentable subject matter. The first step of the Alice/Mayo test addresses whether the patent claims are “directed to” an ineligible concept (i.e., a law of nature, a natural phenomenon, or an abstract idea). To be directed to an ineligible concept, the focus of the claims must be a patent-ineligible concept, as opposed to a technological process. If the patent claims are not directed to an ineligible concept, then the claims are patent-eligible.
> If the claims are directed to an ineligible concept, then the invention is not patentable unless the patent claims have an inventive concept under the second step of the Alice/Mayo test. Step two considers the elements of each patent claim, both individually and as an ordered combination, in determining whether they contain additional aspects that “transform the nature of the claim” into a patent-eligible application of an ineligible concept. Claim limitations that are conventional, routine, and well understood, such as implementing an abstract idea on a generic computer, cannot supply an inventive concept.
An extremely over-reductive TLDR is that the Alice/Mayo test limits patents to specific, concrete, and well understood applications of technology. The test exists because of overly broad patents that essentially attempted to patent the idea of using a computer to do anything as well as attempting to patent ideas that were not yet invented in the hope someone would invent something infringing so they could extract a payday.