If you had a requirement to temporarily (for some time duration) grant access to a permission set or permission set group. This we can achieve now by enabling following feature:
Go to setup. Then, in Quick Find at the top left, type in “User Management Settings”. Next, navigate to the setting called Permission Set & Permission Set Group with Expiration Dates , and turn the switch to Enabled and try to assign permission set and permission set group on user.
Enable this feature: