Webflow's CMS feature has a significant limitation in that the CMS knows nothing about its containing site.
As a result of this design gap, it's currently not possible to link from a CMS collection item to a known page in your site, in the same way you can link within the designer.
CMS's have a Link field type, however a second limitation prevents the use of relative paths, which means you cannot even link to e.g. /about/.
To get around this, we use the hostname self in our absolute links, and then fix-up these links in the published site so that they are relative links.
Below is a collection list showing links from the CMS. Some of these are start with https://self which we fix-up and correct to relative paths.
Click the links below to see their behavior.
Click the View in Webflow's Designer button at the top of this page, to explore the page design.
To add this capability to your own site, see Sygnal Webflow Utils (WFU) documentation here.