Render and display select on post page

I’m using CMB2 plugin to add select metaboxes into a post. The metabox work fine on the post editor. But failed to render and displaying on post page.

The code for post editor

add_action( 'cmb2_admin_init', 'postintro_metabox' );
    function myweb_postintro_metabox() {
    $myweb_grouppf = new_cmb2_box( array(
         'id'            => 'postintro_metabox',
         'title'         => __('Post Intro', 'MYWEB'),
         'object_types' => array( 'post', ), // Post type
         'context'       => 'normal',
         'priority'      => 'high',
         'show_names'    => true, // Show field names on the left
    ) );  

    $myweb_grouppf->add_field( array(
        'name'             => 'Test Select',
        'desc'             => 'Select an option',
        'id'               => 'wiki_test_select',
        'type'             => 'select',
        'show_option_none' => true,
        'default'          => 'custom',
        'options'          => array(
            'standard' => __( 'Option One', 'cmb2' ),
            'custom'   => __( 'Option Two', 'cmb2' ),
            'none'     => __( 'Option Three', 'cmb2' ),
        ),
    ) );

    }

Then I try to call on my post with this code:

<?php echo ( get_post_meta( get_the_ID(), ‘wiki_test_select’, true ) ); ?>

Could you please help me out? I appreciate it.