How to make Two colliders, don't collide, but still be able of interact with each others

Not 100% sure if this is a feature in Unity2D (It should), but all colliders have a small box in their option menu called "Is Trigger". If you check that box on even one of them, then the collider will no longer collide with anything.

If I was you, I would leave the player with just the normal collider to make scripting easier. Then on the zombie, if you still want the zombie to have collision detection, put 2 Box Colliders 2D on it. Check the "Is Trigger" box on one of them.

KEEP READING!!!

 using UnityEngine;
 
 public class Zombie : MonoBehaviour {
     // These are most likely where your variables are
     public bool isTouchingPlayer; // This variable is for detecting when the zombie touches the player
 
 
     // Start is called before the first frame update
     void Start() {
         // Your stuff here...
     }
 
     // Update is called once per frame
     void Update() {
         // Your stuff here...
     }
 
     // NEW STUFF
     private void OnTriggerEnter2D(Collider2D collider) { // This is called when the zombie touches the player
         // Dont forget you need to TAG your player as "Player" for this to work!
         if(collider.tag == "Player") { // This line of code checks to see if the collider it hit is the player!
             // Do stuff here *1
             isTouchingPlayer = true; // This line of code is just an example of what you can do This will make the variable detecting if the zombie touched the player TRUE
         }
     }
     private void OnTriggerExit2D(Collider2D collider) { // This is called when the zombie leaves the player IMPORTANT!!!
         // Basically the same as above
         if(collider.tag == "Player") {
             isTouchingPlayer = false;
         }
     }
 }
 

Something very important to note is at the bottom you will see that there is a *1

Because we are using this from the zombies script, you cant change stuff in the player's script. There are 2 work arounds to this.

A) Use the OnTriggerEnter2D on player object instead

B) Do a bit of extra coding (Ill show an example keep reading ;))

I personally would use B. This is how

You want to make a GameObject variable called "player" and add this short line of code to your update function.

 // This line of code basically gives you access to the PUBLIC variables of the player script
         // Something very important to note is wherever it says "Player" That is where the name of your player's script should go! NOT PLAYER!!!
         Player playerScript = playerGameObject.GetComponent<Player>();
 
         // Here you can go nuts and do whatever when the zombie touches the player
         if (isTouchingPlayer) {
             // For the sake of this example ill just reduce the player's HP
             playerScript.playerHP -= 1;
         }

I've used this method a lot, i hope this helps and the explanation wasn't too confusing. :)

still so hard to figure it out how to do ,,dang