buttonを押した時の画面遷移について

こんにちは。初心者のものです。初質問ですがよろしくお願いします。
現在、plusbuttonを押したら画面遷移を行うということを行っているのですが、タップしても画面遷移が行われません。
どなたか、改善点や修正点のご指摘よろしくお願いします

import UIKit
import MapKit
import CoreLocation

class ViewController: UIViewController ,MKMapViewDelegate,
CLLocationManagerDelegate{

@IBOutlet weak var PlusButton: UIButton!

 var locationManager = CLLocationManager()
 



// MapViewのインスタンス生成.
let mapView = MKMapView()

    

override func viewDidLoad() {
        super.viewDidLoad()
        
locationManager.delegate = self
        
// 画面背景色を設定
self.view.backgroundColor = UIColor(red:0.7,green:0.7,blue:0.7,alpha:1.0)
        
    
PlusButton.layer.zPosition = 2

    }





@IBAction func PlusButton(_ sender: Any) {
performSegue(withIdentifier: "next",sender: nil)



}

    // 画面回転にも対応する
    override func viewDidAppear(_ animated: Bool) {
        var topPadding: CGFloat = 0
        var bottomPadding: CGFloat = 0
        var leftPadding: CGFloat = 0
        var rightPadding: CGFloat = 0
        
        if #available(iOS 11.0, *) {
            // 'keyWindow' was deprecated in iOS 13.0: Should not be used for applications
            let window = UIApplication.shared.windows.filter {$0.isKeyWindow}.first
            topPadding = window!.safeAreaInsets.top
            bottomPadding = window!.safeAreaInsets.bottom
            leftPadding = window!.safeAreaInsets.left
            rightPadding = window!.safeAreaInsets.right
        }
 
        //位置情報サービスの確認
        CLLocationManager.locationServicesEnabled()
 
        // セキュリティ認証のステータス
        let status = CLLocationManager.authorizationStatus()
        
        if(status == CLAuthorizationStatus.notDetermined) {
            print("NotDetermined")
            // 許可をリクエスト
            locationManager.requestWhenInUseAuthorization()
 
        }
        else if(status == CLAuthorizationStatus.restricted){
            print("Restricted")
        }
        else if(status == CLAuthorizationStatus.authorizedWhenInUse){
            print("authorizedWhenInUse")
        }
        else if(status == CLAuthorizationStatus.authorizedAlways){
            print("authorizedAlways")
        }
        else{
            print("not allowed")
        }
 
        // 位置情報の更新
        locationManager.startUpdatingLocation()
        
        
        
        // MapViewをSafeAreaに収める（Portraitのケース）
        // 以降、Landscape のみを想定
        let screenWidth = view.frame.size.width
        let screenHeight = view.frame.size.height
        
        let rect = CGRect(x: leftPadding,
                          y: topPadding,
                          width: screenWidth - leftPadding - rightPadding,
                          height: screenHeight - topPadding - bottomPadding )
        
        mapView.frame = rect
 
        // Delegateを設定.
        mapView.delegate = self
 
        // 縮尺を設定
        var region:MKCoordinateRegion = mapView.region
        region.center = mapView.userLocation.coordinate
        
        region.span.latitudeDelta = 0.04
        region.span.longitudeDelta = 0.04
        
        //画面いっぱい
        mapView.frame = view.bounds
        
        
        
        
        
        mapView.setRegion(region,animated:true)
        // MapViewをViewに追加.
        self.view.addSubview(mapView)
 
        mapView.mapType = MKMapType.hybrid
        
        mapView.userTrackingMode = MKUserTrackingMode.follow
        mapView.userTrackingMode = MKUserTrackingMode.followWithHeading
 
        // MapViewをViewに追加
        self.view.addSubview(mapView)
        
        
    }
    
    func mapView(_ mapView: MKMapView, regionDidChangeAnimated animated: Bool) {
        print("region changed")
    }
    
    
    
    
    
    
    
    
    
  
    
}