Custom multicheck with options_cb

Hello,

I am working with your awesome plugin. I am not so expert with PHP and wordpress and I want to ask you something:

I created this new metabox with the options_cb

function cmb2_guide() {
    $prefix = '_cmb_';

    $cmb = new_cmb2_box( array(
        'id'            => 'categorie_guide_box',
        'title'         => __( 'Categorie Guide', 'cmb2' ),
        'object_types'  => array( 'guide_products', ), // Post type
        'context'       => 'side',
        'priority'      => 'low',
        'show_names'    => true,
    ) );

    $cmb->add_field( array(
    'id'         => $prefix . 'categorie_guide',
    'type'       => 'multicheck',
    'options_cb' => 'get_categorie_catalogo_guide',
	) );
}

and this is my options_cb function:

function get_categorie_catalogo_guide( $query_args ) {
    $args = wp_parse_args( $query_args, array(
        'post_type'   => 'catalogo-guide',
        'numberposts' => -1,
    ) );

    $posts = get_posts( $args );

    $post_options = array();
    if ( $posts ) {
        foreach ( $posts as $post ) {
          $post_options[ $post->ID ] = $post->post_title;
        }
    }

    return $post_options;
}

Now, I have some issues for the front-end part.
Here’s my code in the php page where I need to show the elements:

<?php
$productCat = $post->post_name;

	$args = array(
		'post_type' =>  'guide_products',
		'posts_per_page' => 50,
		'order' => 'ASC'
	);

	$productQuery = new WP_Query( $args );
?>
<?php if($productQuery->have_posts()) : ?><?php while($productQuery->have_posts()) : $productQuery->the_post(); ?>

Now, I need to show all the ‘guide_products’ posts with the $productCat.
I tried to add this option right after ‘order’ but it doesn’t work

'meta_query' => array(
			array(
				'key' => '_cmb_categorie_guide',
				'value' => $productCat
             )
         ),

How should I set it to work correctly?

Thank you so much.

https://wordpress.org/plugins/cmb2/