Cannot implicitly convert type `CarPunteggio' to `GameController'

Here is the code:

 using UnityEngine;
 using System.Collections;
 
 public class PunteggioByContact : MonoBehaviour
 {
     public GameObject explosion;
     public GameObject playerExplosion;
     public int scoreValue;
     private GameController CarPunteggio;
     
     void Start ()
     {
         GameObject CarPunteggioObject = GameObject.FindWithTag ("GameController");
         if (CarPunteggioObject != null)
         {
             CarPunteggio = CarPunteggioObject.GetComponent <CarPunteggio>();
         }
         if (CarPunteggio == null)
         {
             Debug.Log ("Cannot find 'GameController' script");
         }
     }
     
     void OnTriggerEnter(Collider other) 
     {
         if (other.tag == "Boundary")
         {
             return;
         }
         Instantiate(explosion, transform.position, transform.rotation);
         if (other.tag == "Player")
         {
             CarPunteggio.AddScore (scoreValue);
         }
         
         Destroy(other.gameObject);
         Destroy(gameObject);
     }
 }

I cotinue to get this error, and I don't know why:

 Assets/Scripts/PunteggioByContact.cs(16,25): error CS0029: Cannot implicitly convert type `CarPunteggio' to `GameController'