cmb2-display-filters.php

<?php 

function ed_metabox_include_front_page( $display, $meta_box, $cmb ) {
    if ( ! isset( $meta_box['show_on']['key'] ) ) {
        return $display;
    }

    if ( 'front-page' !== $meta_box['show_on']['key'] ) {
        return $display;
    }

    $post_id = 0;

    // If we're showing it based on ID, get the current ID
    if ( isset( $_GET['post'] ) ) {
        $post_id = $_GET['post'];
    } elseif ( isset( $_POST['post_ID'] ) ) {
        $post_id = $_POST['post_ID'];
    }

    if ( ! $post_id ) {
        return false;
    }

    // Get ID of page set as front page, 0 if there isn't one
    $front_page = get_option( 'page_on_front' );

    // there is a front page set and we're on it!
    return $post_id == $front_page;
}
add_filter( 'cmb2_show_on', 'ed_metabox_include_front_page', 10, 3 );

function ed_metabox_show_on_species_page( $display, $meta_box, $cmb ) {
    if ( ! isset( $meta_box['show_on']['key'] ) ) {
        return $display;
    }

    if ( 'species-page' !== $meta_box['show_on']['key'] ) {
        return $display;
    }

    $post_id = 0;

    // If we're showing it based on ID, get the current ID
    if ( isset( $_GET['post'] ) ) {
        $post_id = $_GET['post'];
    } elseif ( isset( $_POST['post_ID'] ) ) {
        $post_id = $_POST['post_ID'];
    }

    if ( ! $post_id ) {
        return false;
    }

    // Get ID of page set as front page, 0 if there isn't one
    $species_page = 7;

    // there is a front page set and we're on it!
    return $post_id == $species_page;
}
add_filter( 'cmb2_show_on', 'ed_metabox_show_on_species_page', 10, 3 );