why my post not redirecting to custom created single-show.php file?

by

Simply use default WordPress loop for single pages of post types…

<?php 
if ( have_posts() ) {
    while ( have_posts() ) {
        the_post(); 
        echo '<h1>'.get_the_title().'</h1>';
        // Post Content here
    } // end while
} else{
   esc_html_e( 'Sorry, no posts found.' );
}
?>