The best way to do that would be to create a custom page template, and make a custom loop that would only display the posts in you specific category and tag.
For example:
global $wp_query; $args = array( 'category__and' => 'category', 'tag__in' => 'post_tag', //Enter tag id for this field (not tah name) 'posts_per_page' => -1); //Gets all posts $posts = get_posts($args); foreach ($posts as $post) : endforeach;