WP:Include template files from plugin

gistfile1.php

<?php

// In this situation, template files for your custom post type will live in the root of your plugin directory.
// Ideally they would be in a subdirectory.

add_filter( 'archive_template', 'get_archive_template' );
function get_archive_template( $archive_template ) {
  global $post;
  $plugindir = dirname( __FILE__ );
  
  if( get_query_var( 'post_type' ) == 'your_custom_post_type' ) {
    $archive_template = $plugindir . '/custom_post_type_archive.php';
  }
  return $archive_template;

}

add_filter( 'search_template', 'get_search_template' );
function get_search_template( $search_template ) {
  global $post;
  $plugindir = dirname( __FILE__ );
  
  if( get_query_var( 'post_type' ) == 'your_custom_post_type' ) {
    $search_template = $plugindir . '/custom_post_type_archive.php';
  }
  return $search_template;

}

add_filter( 'single_template', 'get_single_template' );
function get_single_template( $single_template ) {
  global $post;
  $plugindir = dirname( __FILE__ );
  
  if( get_query_var( 'post_type' ) == 'your_custom_post_type' ) {
    $single_template = $plugindir . '/custom_post_type_single.php';
  }
  return $single_template;

}