This may be useful. Instagram will start showing you the number of inactive accounts within your list of followers so you can unfollow them if you'd like to.
you can now swipe through on your "Followers" list when you tap on it from your IG profile, and you'll find a new section above the main list that shows you "Deactivated accounts," profiles that have been flagged for review, creator accounts, etc.

Why unfollow these inactive accounts?

Well, for one, they're messing up your stats: all of your average performance figures are divided by the total number of followers you have. So your engagement rates and reach data could be impacted depending on how you measure them (Note: Instagram's pushing users towards "views" as the primary metric and this won't be impacted by inactive profiles following your account).

They could also be messing up your ad targeting sets if you're looking to target people like the audience that you already have. That's the same with asking family members to follow your brand account, at some stage you might be better off removing them because all of your insights into your audience's interests could be affected by having people outside of your target audience included in this segment.

Inactive followers may be the same, with accounts which are not active still being included in your datasets.

But now you can easily remove them-they can do this by simply going to this listing and tapping "Remove" on each account.

Of course, you might also want to retain them because perhaps getting a higher number of followers is significant to you. However, depending upon the manner in which you seek to grow your profile and reach the appropriate audience within the app, being able to delete inactive profiles may prove a great addition to your workflow.

The new option is now available within the latest iteration of Instagram.