Instagram is making a minor, though useful, change in the bios of today's users: when you mention another account or hashtag in your profile, it will show a real link that other users can access. So, for example, I have @verge in my profile. Before this change, it was just regular text and not an appropriate link. But Instagram has been dedicated to changing that.
And if you have a loved hashtag, you can also put it in your biography, and it will link to recently uploaded photos that have the same hashtag in your description or comments. Instagram added the ability to track hashtags in your main feed, along with people's posts you follow, in December.
But if you want to include a real link to a URL outside of Instagram in your biography, you can only do so in the "website" field when editing your profile. These new interactive profile components are designed to keep you reading Instagram.