Where standards setters can agree and collaborate on certain areas (list of country codes, list of energy sources), it can make sense to define the list once and then make use of it in both standards. This situation can often occur when multiple standards derive from the same top standard.
Example
An example code-list is the below energy source list:

Two otherwise different and independent taxonomies (taxonomy-a and taxonomy-b) can both use above common “Energy Source” code list as a dimension:

Links
Example using taxonomy A (and using shared energy source list):
Inline Viewer – CarMaker Sustainability Disclosure (xbrl.org)
Example using taxonomy B (and using shared energy source list):
Inline Viewer – Van Build Inc Sustainability Disclosure (xbrl.org)
Taxonomy and report package:
https://xii.ci.xbrl.org/ixbrl-samples/xii-sig-dsd-meeting-8/xii-sig-dsd-example-9.zip