How do I lock my Players Y axis to my Cameras?

I've been messing around with trying to build some form of an FPS game the past 3 days, and I've gotten myself into using mouse input for my camera. I've therefore encountered this rather annoying problem where I can move my camera around, but my player object does not follow its Y-axis which is what I want.

How would I be able to add this to my code?

My Camera Script looks as following ( Please note I'm entirely new to Unity and I've used help online for the code ):

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class Mouse : MonoBehaviour { public float sensitivityX = 15F; public float sensitivityY = 15F;

 public float minimumLockX = -60F;
 public float maximumLockX = 60F;

 public float minimumLockY = -360;
 public float maximumLockY = 360;

 public Camera CameraObject;
 public GameObject PlayerObject;

 private float rotationX = 0;
 private float rotationY = 0;

 void Start()
 {
     Cursor.lockState = CursorLockMode.Locked;
     Cursor.visible = false;
 }


 void Update()
 {
     rotationY += Input.GetAxis("Mouse X") * sensitivityY;
     rotationX += Input.GetAxis("Mouse Y") * sensitivityX;

     rotationX = Mathf.Clamp(rotationX, minimumLockX, maximumLockX); 

     CameraObject.transform.localEulerAngles = new Vector3(-rotationX, rotationY, 0);



     if (Input.GetKey(KeyCode.Escape)) 
     {
         Cursor.lockState = CursorLockMode.None;
         Cursor.visible = true;
     }
 }

}