why won’t express app.post render my view?

I’ve seen the same question posted, but not many helpful answers. I would like to render the welcome page once I’ve done content of the app.post, but nothing happens.

I know it’s valid as it will give me an error if i enter an invalid route, but it just will not do what i would like.

 app.get('/', function (req, res) {
    res.render('Welcome')
  })    
 
app.post('/makepost', function (req, res) {
    //do some things
    res.render('Welcome');
  })

In the View I use this to call the app.post.

fetch('/makepost', {
                    method: 'POST', 
                    headers: {
                        'Content-Type': 'application/json',
                    },
                    body: body,
                }