What am I doing wrong?

Questions & Answers
1

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

public class PlayerMovement : MonoBehaviour {
private Vector3 pos;

void Start () {
	
}

void Update () {
    if (Input.GetKey("w")) {
        pos.z = pos.z + 0.1f;
    }
    if (Input.GetKeyDown("s")) {
        pos.z = pos.z - 0.1f;
    }
}

}

The player doesn’t move when I press w or s even though there aren’t any compiler errors.

2

Whilst you have a Vector3 variable for position, and you change it, you’re never actually telling your objects transform to assume that vector as its position.

try using this update.

void Update () 
{
	pos = transform.position;
	
     if (Input.GetKey("w")) 
     {
         pos.z = pos.z + 0.1f;
     }
     if (Input.GetKeyDown("s")) 
     {
         pos.z = pos.z - 0.1f;
     }
     
     transform.position = pos;
 }

Keep in mind that this sort of movement will be frame-rate dependant, so it might be worth having a “speed” variable and then multiplying your increment/decrement of the z value by (speed * Time.deltaTime), just a suggestion.