CameraFollow.cs

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

public class CameraFollow : MonoBehaviour
{
    public Transform m_Target;

    public float m_offsetHeight = 7;
    public float m_offsetDistance = 12;
    public float m_lerpTime = 0.4f;

    // Use this for initialization
    private void Start ()
    {
        if (m_Target == null)
        {
            Debug.LogError("CameraFollow: Missing Target!");
        }
    }

    private void FixedUpdate()
    {
        if (m_Target != null)
        {
            Vector3 offset = m_Target.forward * -m_offsetDistance + (Vector3.up * m_offsetHeight);
            transform.position = Vector3.Lerp(transform.position, m_Target.position + offset, m_lerpTime * Time.deltaTime);
            transform.LookAt(m_Target);
        }
    }
}