Thanks for the responses.
If it’s in a case context, you can have it as URL field with the link of your non-pega application populated for it and by default when you click on the link it will open in new tab.
If you want it on the portal dashboard aloof from the case, then you show them as list view rendered as gallery cards with the link populated in it. You might need an abstract class with URL field along with a data page of type list for it to display the list of cards.
You can refer to the below post for more insights
Hope this helps
Regards
JC