Using Cypress to Test an App That Relies on OAuth

I've inherited a Node.js web app that uses relies on OAuth. Whenever you visit a page the app ensures you've authenticated. Please note, there no Angular, React, Vue, etc here. Each page is straight up HTML.

I want to test this site using Cypress. My problem is, I'm stuck on the initial redirect from the auth provider. Cypress acknowledge OAuth is a challenge.

commands.js

Cypress.Commands.add('login', (credentials) => {
  var settings = {
    'clientId':'<id>',
    'scope':'<scope-list>',
    ...
  };

  var body = `client_id=${settings.clientId}&scope=${settings.scope}...`;

  var requestOptions = {
    method: 'POST',
    url: 'https://login.microsoftonline.com/...',
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded'
    },
    body: body
  }

  cy.request(requestOptions);
});

Then, in my test, I have:

context('Home', () => {
  it('Visits Successfully', () => {
    cy.login();

    cy.title().should('include', 'welcome');
  });
});

In the test runner, I see the login POST request is occurring. I confirmed that an access token is being received using a console.log, however, my title is empty. It's like the redirect after OAuth isn't happening in Cypress. However, when I visit the site in the browser, the redirect is happening as expected.

What am I missing?