$args['post_tax_filter'] = array();
// Exclude posts from categories 1,2,3,4 and include from 5,6,7,8
$args['post_tax_filter'] = array(
'taxonomy' => 'category',
'include' => array(1, 2, 3, 4),
'exclude' => array(5, 6, 7, 8),
'allow_empty' => true // Allow results, that does not have connection with this taxonomy
// Exclude Posts from certain categories, include from certain tags
$args['post_tax_filter'] = array(
'taxonomy' => 'category',
'exclude' => array(5, 6, 7, 8)
'taxonomy' => 'post_tag',
'include' => array(10, 11, 23, 44),