Look around camera with mouse - Unity

UnityFreeCamera.cs

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

public class FreeCamera : MonoBehaviour
 {
     public float sensitivity = 10f;
     public float maxYAngle = 80f;
     private Vector2 currentRotation;
     void Update()
     {
         currentRotation.x += Input.GetAxis("Mouse X") * sensitivity;
         currentRotation.y -= Input.GetAxis("Mouse Y") * sensitivity;
         currentRotation.x = Mathf.Repeat(currentRotation.x, 360);
         currentRotation.y = Mathf.Clamp(currentRotation.y, -maxYAngle, maxYAngle);
         Camera.main.transform.rotation = Quaternion.Euler(currentRotation.y,currentRotation.x,0);
         if (Input.GetMouseButtonDown(0))
             Cursor.lockState = CursorLockMode.Locked;
     }
 }

A simple script to look around with the game's camera using the mouse. Useful to debug on the game view.