A Template to use with Input System Package in Unity Engine

PlayerController.cs

using UnityEngine;
using UnityEngine.InputSystem;

public class PlayerController : MonoBehaviour
{
    /*
     * mov: stores movement data and related logic
     * dir: stores direction data and related logic
     * pos: (UI Map) stores mouse/pointer position data and related logic
     * vel: stores vertical velocity value for gravity
     * cam: camera attached on Player Input component's Camera field
     *
     * Player Input component's Behavior should be set to Send Messages
     */
    Vector2 mov; // WASD, Left Stick
    Vector2 dir; // Mouse, Right Stick
    Vector2 pos; // Pointer Position (when UI/Point map is active)
    Vector3 vel; // y value for gravity

    Camera cam; // Player Input's Camera, or fallbacks to Main Camera
    Transform camT; // camera's transform
    Transform body; // transform this script is attached to
    CharacterController controller; // character controller of the gameobject

    [Header("Movement")]
    [SerializeField] float speed = 5f;
    [SerializeField] float gravity = -9.81f;

    [Header("Look")]
    [SerializeField] float mouseSensitivity = 8f;
    readonly float sensitivityEditorAdjustment = 3f;
    float xRotation = 0f;

    [Header("Interact")]
    [SerializeField] float interactMaxDistance = 10f;
    [SerializeField] LayerMask interactMask = ~0;

    void Awake()
    {
        controller = GetComponent<CharacterController>();
        body = transform;

        PlayerInput pi = GetComponent<PlayerInput>();
        cam = pi && pi.camera ? pi.camera : Camera.main;
        camT = cam ? cam.transform : null;

        mouseSensitivity *= Application.isPlaying ?
            sensitivityEditorAdjustment : 1f;

        Cursor.lockState = CursorLockMode.Locked;
        Cursor.visible = false;
    }
    void OnMove(InputValue v) => mov = v.Get<Vector2>(); 
    void OnLook(InputValue v) => dir = v.Get<Vector2>();
    void OnPoint(InputValue v) => pos = v.Get<Vector2>();
    void OnInteract()
    {
        Vector2 position = (pos.sqrMagnitude > 0f) ?
            pos :
            (
                Mouse.current != null ?
                    Mouse.current.position.ReadValue() :
                    new Vector2(Screen.width * .5f, Screen.height * .5f)
            );

        Ray ray = cam.ScreenPointToRay(position);
        if (Physics.Raycast(
            ray, out RaycastHit hit, interactMaxDistance, interactMask
        ))
        {
            hit.collider.gameObject.SendMessage(
                "OnInteract",
                SendMessageOptions.DontRequireReceiver
            );
        }
    }

    void Update()
    {
        float dT = Time.deltaTime;

        // movement
        if (controller)
        {
            Vector3 m = (body.right * mov.x + body.forward * mov.y) * (speed * dT);
            if (controller.isGrounded && vel.y < 0f) vel.y = -2f;
            vel.y += gravity * dT;
            controller.Move(m + dT * vel);
        }

        // look
        if (camT)
        {
            float dX = mouseSensitivity * dT * dir.x;
            float dY = mouseSensitivity * dT * dir.y;
            xRotation = Mathf.Clamp(
                xRotation - dY,
                -90f,
                90f
            ); // pitch
            camT.localRotation = Quaternion.Euler(xRotation, 0f, 0f);
            body.Rotate(Vector3.up * dX); // yaw
        }
    }
}