Microsoft has announced that Wiki’s will be retired from Teams in mid February. If you are using Wiki in Teams, you can export your Wiki content to OneNote Notebooks.
When this will happen:
The following change will be rolled out starting mid-February
How this affects your organization:
With this release, users have an option to export their wiki content to OneNote notebooks in Teams standard channel. After exporting users can go to the Notes tab to collaborate using OneNote in channels.
Note: With this change users can continue to access and edit existing wikis but can’t create new wikis in Teams channels.