get_template_part() does not work if you call it when you are in a subfolder

get_template_part() will work the same no matter where or how deep you are within your theme. It always includes relative to the theme (or child theme) root.

So if you call the following from anywhere:

get_template_part( 'content', 'job-listing' );

… it will try to load (in order):

1. child-theme/content-job-listing.php
2. parent-theme/content-job-listing.php
3. child-theme/content.php
4. parent-theme/content.php

To load parts that are in a subdirectory of your theme, just use the path in the first argument:

get_template_part( 'path/to/file', 'optional-slug' );