Remove 'cancel' button for gifted subscriptions only.

remove_cancel_gifted_subs.php

<?php

function remove_cancel_gifted_subs( $actions, $subscription ) {

  if ( WCS_Gifting::is_gifted_subscription( $subscription ) ) {

    foreach ( $actions as $action_key => $action ) {
      switch ( $action_key ) {
          case 'cancel':			// Hide "Cancel" button on subscriptions that are "active" or "on-hold"?
          unset( $actions[ $action_key ] );
          break;
        default: 
          error_log( '-- $action = ' . print_r( $action, true ) );
          break;
      }
    }

  }
	return $actions;
}
add_filter( 'wcs_view_subscription_actions', 'remove_cancel_gifted_subs', 100, 2 );