// first query
$first_ids = get_posts( array(
'fields' => 'ids',
'posts_per_page' => '10',
'post_status' => 'publish',
'post_type' => array('news','partners'),
'orderby' => 'date',
'order' => 'DESC'
));
// second query
$second_ids = get_posts( array(
'fields' => 'ids',
'posts_per_page' => '10',
'post_status' => 'publish',
'post_type' => array('post'),
'orderby' => 'date',
'order' => 'DESC',
'tax_query' => array(array(
'taxonomy' => 'tax',
'field' => 'term_id',
'terms' => array(5)
))
));
// merging ids
$post_ids = array_merge( $first_ids, $second_ids);
// the main query
$query = new WP_Query(array(
'post_type' => 'any',
'post__in' => $post_ids,
'orderby' => 'date',
'order' => 'DESC'
));
if( $query->have_posts() ):
// here you go
endif;