Unity click to move and player controls

c#

using System;
using UnityEngine;
using UnityEngine.AI;

public class PlayerMove : MonoBehaviour
{
    CharacterController CharacterController;
    public Camera CharacterCamera;
    public float Speed = 6.0f;
    public float JumpSpeed = 8.0f;
    public float Gravity = 20.0f;
    public Vector3 ClickedToWalk;
    private NavMeshAgent NavMeshAgent;

    private Vector3 MoveDirection = Vector3.zero;

    void Start()
    {
        CharacterController = GetComponent<CharacterController>();
        NavMeshAgent = GetComponent<NavMeshAgent>();
    }

    void Update()
    {
        if (!NavMeshAgent.isStopped && Vector3.Distance(NavMeshAgent.transform.position, ClickedToWalk) < 0.5f ||
            (Input.GetKeyDown(KeyCode.W) ||
                Input.GetKeyDown(KeyCode.A) ||
                Input.GetKeyDown(KeyCode.S) ||
                Input.GetKeyDown(KeyCode.D)))
        {
            // Stop auto-navigation
            NavMeshAgent.isStopped = true;
        }

        if (Input.GetMouseButtonDown(0))
        {
            Ray ray = CharacterCamera.ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;

            if (Physics.Raycast(ray, out hit, 100.0f))
            {
                if (hit.transform.gameObject.layer == LayerMask.NameToLayer("Walkable"))
                {                    
                    ClickedToWalk = hit.point;

                    NavMeshAgent.isStopped = false;
                    NavMeshAgent.SetDestination(hit.point);
                }
                else
                {
                    NavMeshAgent.isStopped = false;
                }
            }
        }


        if (NavMeshAgent.isStopped)
        {
            // Calculate move direction directly from axes
            MoveDirection = Quaternion.Euler(0, CharacterCamera.transform.eulerAngles.y, 0) * new Vector3(Input.GetAxis("Horizontal"), 0.0f, Input.GetAxis("Vertical"));
            if (MoveDirection != Vector3.zero)
            {
                print("c");
                MoveDirection *= Speed;

                // Apply gravity. Gravity is multiplied by deltaTime twice (once here, and once below
                // when the moveDirection is multiplied by deltaTime). This is because gravity should be applied
                // as an acceleration (ms^-2)
                MoveDirection.y -= Gravity * Time.deltaTime;

                // Move the controller
                CharacterController.Move(MoveDirection * Time.deltaTime);
            }
        }
    }
}