$choice = get_field('menu_item_type');
if ($choice == 'checkbox') {
// do something
} elseif ($choice == 'product') {
$product = get_field('pdp_product_one');
// get an acf field from the product
$some_value = get_field('some_field', $product->ID);
// get something else from the product
// see documentation for what you are using for products
}