<?php
// Example query to select all posts belonging to a custom taxonomy.
$args = array(
	'tax_query' => array(
		array(
			'taxonomy' => 'TAXONOMY_NAME',
			'field' => 'slug',
			'terms' => 'TAXONOMY_SLUG'
		)
	)
);
$the_query = new WP_Query( $args );

// The Loop
while ( $the_query->have_posts() ) : $the_query->the_post();
	echo '<li>';
	the_title();
	echo '</li>';
endwhile;

// Reset Post Data
wp_reset_postdata();
?>

Use WP_Query to query a custom taxonomy, using the tax_query parameter.

Wordpress: Query a custom taxonomy

wordpress

PHP