How do I load the current items in cart of the anonymous user?
Get the current anonymous user's cart

  $cart_provider = \Drupal::service('commerce_cart.cart_provider');
  $cart = $cart_provider-&gt;getCart('default');


Get a list of items still in that user's cart

$order_items = $cart-&gt;order_items-&gt;referencedEntities();


Bonus
$cart_manager = \Drupal::service('commerce_cart.cart_manager');

Update order item
$cart_manager-&gt;updateOrderItem($cart, $order_item);

Remove order item
$cart_manager-&gt;removeOrderItem($cart, $order_item);

Empty cart
$cart_manager-&gt;emptyCart($cart);

Create order item
$order_item = $cart_manager-&gt;createOrderItem($entity, $quantity);

Add order item
$cart_manager-&gt;addOrderItem($order_item);