Implied patent licenses:
https://www.wilmerhale.com/pages/publicationsandnewsdetail.a....
https://copyleft.org/guide/comprehensive-gpl-guidech7.html
Basically, if you sell or license a product that requires a patent to work, courts have generally held that you grant an implied patent license for any patents that the product might require. If you explicitly reference patents within the license, however, then whatever terms you explicitly write into the license supersede this implied patent license. BSD+patents (and Apache 2) have explicit patent language; paradoxically, this makes them more restrictive than licenses like MIT, BSD, or GPL that don't mention patents at all.
Apache 2.0 certainly doesn't require you to have patents in order to use it ("applies only to those patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s)")