player transforming in both x and z axis when using translate unity code example

Example: transform.Translate movement

using UnityEngine;
using System.Collections;public class ExampleClass : MonoBehaviour
{
    void Update()
    {
        // Move the object forward along its z axis 1 unit/second.
        transform.Translate(Vector3.forward * Time.deltaTime);        // Move the object upward in world space 1 unit/second.
        transform.Translate(Vector3.up * Time.deltaTime, Space.World);
    }
}