There are three options for you to share the Sublist with: Project Members, External Team and Personal (yourself).
You won’t be able to change the permission once it has been set.
Learn how to create a Sublist.
Share Sublist with project members
The newly created Sublist will be visible to all of the project members (excluding the External Team). There’s no way to customize to selected project members.
Share Sublist with External Team
When creating a new Sublist and setting the permission to External Team, you can only select the tasks that have already been assigned to External Team.
All of the members in the External Team can view the tasks within this Sublist. When the tasks are added, they will automatically be assigned to the External Team.
If you add a parent task with an already assigned subtask to this Sublist, the subtask will not be reassigned to the External Team, it will still be assigned to the original assignee.
Create a personal Sublist
The newly created Sublist will be visible to you only. Other project members cannot view or edit the Sublist even with the shared link.