Show current custom taxonomy

You can use get_the_terms() to retrieve terms from a custom taxonomy which are attached to a post.

In your Loop you could do the following to retrieve the terms,

$departments = get_the_terms( get_the_ID(), 'department' );

This gives you an array of WP_Terms. If for example, you want to use just the first one you could do it like this.

echo ($departments && is_array($departments) ? $departments[0]->name : '';