Cat query
$tax_query = array( 'relation' => 'OR', array( 'taxonomy' => 'category', 'terms' => array( 'news', 'altro' ), 'field' => 'slug', ), );
$tax_query = array( 'relation' => 'OR', array( 'taxonomy' => 'category', 'terms' => array( 'news', 'altro' ), 'field' => 'slug', ), );