sb_schoolpergem

// WP_Query arguments
$args = array(
	'post_type'              => array( 'sb_school' ),
	'tax_query'              => array(
		array(
			'taxonomy'         => 'sb_membership',
			'terms'            => '2020-2021',
			'field'            => 'slug',
		),
	),
	'meta_query'             => array(
		array(
			'key'     => 'sch-postcode',
			'compare' => 'IN',
		),
	),
);

// The Query
$scholen_01 = new WP_Query( $args );

// The Loop
if ( $scholen_01->have_posts() ) {
	while ( $scholen_01->have_posts() ) {
		$scholen_01->the_post();
		// do something
	}
} else {
	// no posts found
}

// Restore original Post Data
wp_reset_postdata();