Thumbnail With Next/Prev Links Not Showing Next Post?

After trying to ask help from others, I got my solution and here I am sharing that below. First there is no use of 'in_same_cat' => false, in upper code and second get_next_post(true);, get_previous_post(true); is used to show next/prev post from current post categories but if you want to show all posts in next/prev then you have to use only get_next_post();, get_previous_post(); instead of upper one. Finally the working code is shared below.

<!-- Pagination -->
<div id="post_pagination">
    <?php $nextPost = get_next_post();
        if($nextPost) {
            $args = array(
                'posts_per_page' => 1,
                'include' => $nextPost->ID
            );
            $nextPost = get_posts($args);
            foreach ($nextPost as $post) {
                setup_postdata($post);
    ?>
        <a href="https://wordpress.stackexchange.com/questions/169189/<?php the_permalink(); ?>"><div class="post_next_post">
            <?php the_post_thumbnail('thumbnail'); ?>
            <span class="next">Next Story &raquo;</span>
            <h4><?php the_title(); ?></h4>
        </div></a>
    <?php
                wp_reset_postdata();
            } //end foreach
        } // end if
    ?>
    <?php $prevPost = get_previous_post();
        if($prevPost) {
            $args = array(
                'posts_per_page' => 1,
                'include' => $prevPost->ID
            );
            $prevPost = get_posts($args);
            foreach ($prevPost as $post) {
                setup_postdata($post);
    ?>
        <a href="https://wordpress.stackexchange.com/questions/169189/<?php the_permalink(); ?>"><div class="post_prev_post">
            <?php the_post_thumbnail('thumbnail'); ?>
            <span class="prev">&laquo; Previous Story</span>
            <h4><?php the_title(); ?></h4>
        </div></a>
    <?php
                wp_reset_postdata();
            } //end foreach
        } // end if
    ?>
</div>
<!-- Pagination -->