Here is a sample of JSON formatting for multi-choice column to produce the expected result.
I think you have to create a lookup column for this.
Create a lookup column in QuanLyMembers list referencing to QuanLyPhongBan list.
Check below note from Microsoft:
There are requirements to keep in mind when creating list joins. You cannot join just any two lists, regardless of type. And if two lists can be joined, not just any primary and foreign field ...