Try to push new viewController(InboxController) from rootViewController , rootViewController is UITabBar. But, pushViewController not showing anything and only show rootViewController

          // 1
          guard let tabBarController = window?.rootViewController as? UITabBarController else {
            return
          }

          // 2
          guard let tabBarControllers = tabBarController.viewControllers,
            let listIndex = tabBarControllers.firstIndex(where: { $0 is UINavigationController }),
            let listViewController = tabBarControllers[listIndex] as? UINavigationController else { return }

        
          // 3
          listViewController.popToRootViewController(animated: false)
          tabBarController.selectedIndex = listIndex
        
          // 4
          let detailViewController = InboxController()
          listViewController.pushViewController(detailViewController, animated: true)
        
        window?.rootViewController = listViewController
        window?.makeKeyAndVisible()