Displaying a div from an assigned meta_value when on a page

If you just want to check if a meta value exists before outputting markup, then

if( get_post_meta( $post->ID, '_cmb_linkCheckbox', true ) ){
    ?>
    <section id="footerLinks">
        <?php // your markup... ?>
    </section>
    <?php
}

or if the value is “on”:

if( 'on' == get_post_meta( $post->ID, '_cmb_linkCheckbox', true ) ){
    // etc..
}