[{_id:"ObjectId1",status:"WAITING","members":[{"_id":"ID1"}]},{_id:"ObjectId2",status:"WAITING","members":[{"_id":"ID2"}]},{_id:"ObjectId3",status:"ENDED","members":[{"_id":"ID1",},{"_id":"ID2",}]}]

db.collection.aggregate([{$match:{status:"ENDED"}},{$unwind:"$members"},{$match:{"members._id":"ID2"}}])