Found answer by myself:

The route of that URL should be @http.route('/dataset/<string:tracking_number>', type='http or json', auth="user or public"), basically the method should be like this:

import json

from odoo import http
from odoo.http import Response, request

class tracking(http.Controller):
    # if user must be authenticated use auth="user"
    @http.route('/dataset/<string:tracking_number>', type='http', auth="public")
    def tracking(self, tracking_number):  # use the same variable name
        result = # compute the result with the given tracking_number and the result should be a dict to pass it json.dumps
        return Response(json.dumps(result), content_type='application/json;charset=utf-8',status=200)

This method accept http request and return a json response, if the client is sending a json requests you should change type='json'. don't forget to import the file in the __init___.py.

Lets take an example let say that I want to return some information about a sale.order by a giving ID in the URL:

import json

from odoo import http
from odoo.http import Response, request

 class Tracking(http.Controller):
    @http.route('/dataset/<int:sale_id>', type='http', auth="public")
    def tracking(self, sale_id):
        # get the information using the SUPER USER
        result = request.env['sale.order'].sudo().browse([sale_id]).read(['name', 'date_order'])
        return Response(json.dumps(result), content_type='application/json;charset=utf-8',status=200)

So when I enter this URL using my Browser: http://localhost:8069/dataset/1: