Backend Server fetching data vs UI fetching data

I have an architecture question.

I am currently working on a system architecture for an Employee information system which will show all the employee information. But the information what needs to be shown to user is currently stored in two systems. But on UI for user we need to show the data in consolidated view. We have two option to approach this.

Option#1:

One backend server which fetches both the data from the two systems and then send it UI to display.

Option#2:

One backend server sends the data from one system and links to get the data from other system.UI then fetches the data from other system to display it on UI.

According to me the Option#2 is better since the data is fetched by UI as and when needed. But the concern with this approach is UI needs to make repeated calls to system2 which makes lot of HTTP requests.

Can I get suggestions on which option is better and why?