WooCommerce - Remove subtotal row.

gistfile1.txt

add_filter( 'woocommerce_get_order_item_totals', 'adjust_woocommerce_get_order_item_totals' );

function adjust_woocommerce_get_order_item_totals( $totals ) {
  unset($totals['cart_subtotal']  );
  return $totals;
}

@christ12345 @PiotrKrzyzek @mstudioIL
To hide the "Subtotal:" row on the Cart and Checkout pages, add this code to style.css:
.cart-subtotal {display: none;}
upd. @mikejolley's code removes the "Subtotal:" row from the Order Received page (and, therefore, from emails).

Did u try to hook to woocommerce_cart_item_subtotal ?
something like this:
function cart_subtotal_func_unset( $total ) {
unset($totals['cart_subtotal']);
return $totals;
}
add_filter('woocommerce_cart_item_subtotal', 'cart_subtotal_func_unset', 10, 2);

@DanBeezy, It still shows in mobile, how to hide it in mobile also.

@jaibojo

To remove Subtotal row (in mobile also) add this code to style.css
.cart-subtotal { display: none !important; }

This is the answer for removing the subtotal from the cart and checkout pages
https://stackoverflow.com/questions/53277895/remove-subtotal-line-from-cart-and-checkout-pages-in-woocommerce