PlayerController.cs

using UnityEngine;

public class PlayerController : MonoBehaviour
{

    public float speed = 3;
    //public Animator animator;
    // camera and rotation

    public float mouseSensitivity = 2f;
    public float upLimit = -50;
    public float downLimit = 50;


    public Transform cameraHolder;
    public CharacterController characterController;


    // gravity
    private float gravity = 9.87f;
    private float verticalSpeed = 0;

    void Update()
    {
        Move();
        Rotate();
    }

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

    private void Rotate()
    {
        float horizontalRotation = Input.GetAxis("Mouse X");
        float verticalRotation = Input.GetAxis("Mouse Y");

        transform.Rotate(0, horizontalRotation * mouseSensitivity, 0);
        cameraHolder.Rotate(-verticalRotation * mouseSensitivity, 0, 0);

        Vector3 currentRotation = cameraHolder.localEulerAngles;
        if (currentRotation.x > 180) currentRotation.x -= 360;
        currentRotation.x = Mathf.Clamp(currentRotation.x, upLimit, downLimit);
        cameraHolder.localRotation = Quaternion.Euler(currentRotation);
    }

    private void Move()
    {
        float horizontalMove = Input.GetAxis("Horizontal");
        float verticalMove = Input.GetAxis("Vertical");

        //if (characterController.isGrounded) verticalSpeed = 0;
        //else verticalSpeed -= gravity * Time.deltaTime;
        //Vector3 gravityMove = new Vector3(0, verticalSpeed, 0);

        Vector3 move = transform.forward * verticalMove + transform.right * horizontalMove;
        characterController.Move(speed * Time.deltaTime * move /*  + gravityMove * Time.deltaTime */);

        //animator.SetBool("isWalking", verticalMove != 0 || horizontalMove != 0);

    }
}