db={"orders":[{"_id":ObjectId("605a4220f63203772c882288"),"candidate":[{"groupId":"B","autonomousId":[ObjectId("601817ef2eeecd17db3a68f7")]},{"groupId":"A","autonomousId":[ObjectId("601817dc2eeecd17db3a68f6")]},]},{"_id":ObjectId("60511faed85e494804be5637"),"candidate":[{"groupId":"A","autonomousId":[ObjectId("6014629b3134774bddebaf7a"),ObjectId("601817dc2eeecd17db3a68f6")]},{"groupId":"C","autonomousId":[ObjectId("601817ef2eeecd17db3a68f7")]}],},],"users":[{"_id":ObjectId("601817dc2eeecd17db3a68f6"),"name":"Maria",},{"_id":ObjectId("601817ef2eeecd17db3a68f7"),"name":"Jose",},{"_id":ObjectId("6014629b3134774bddebaf7a"),"name":"Joao",}]}

db.orders.aggregate([{$unwind:"$candidate"},{$match:{"candidate.groupId":"A"}},{$lookup:{from:"users",let:{id:"$candidate.autonomousId"},pipeline:[{$match:{$expr:{$in:["$_id","$$id"]}}}],as:"candidateData",},},])