<?php
function wpforum218064_recommend_posts() {
    global $post;

    if ( ! is_single() ) {
        return;
    }

    $html      = '';
    $meta_key  = 'products-cate';
    $products  = get_post_meta( $post->ID, $meta_key, true );
    $meta_args = array(
        'relation' => 'OR',
    );

    if ( ! empty( $products ) ) {
        foreach ( $products as $product ) {
            $product     = (int) $product;
            $meta_args[] = array(
                'key'     => $meta_key,
                'value'   => '"' . $product . '"',
                'compare' => 'LIKE',
            );
        }
    }

    $args = array(
        'post_type'    => array( 'post', 'page' ),
        'meta_query'   => $meta_args,
        'post__not_in' => (array) $post->ID,
    );
    $query = new WP_Query( $args );
    $html .= '<ul>';

    while ( $query->have_posts() ) {
        $query->the_post();
        $html .= '<li><a href="' . get_permalink() . '">' . get_the_title() . '</a></li>';
    }

    $html .= '</ul>';

    wp_reset_postdata();

    echo $html;
}