Array
(
    [post_type] => post
    [tax_query] => Array
        (
            [relation] => AND
            [0] => Array
                (
                    [taxonomy] => category
                    [field] => id
                    [terms] => 15
                )

            [1] => Array
                (
                    [taxonomy] => post_tag
                    [field] => id
                    [terms] => 21
                )

        )

    [posts_per_page] => 6
    [paged] => 1
)