Database

[{"appId":"1","targetFrom":"a","targetTo":"b"},{"appId":"1","targetFrom":"b","targetTo":"c"},{"appId":"1","targetFrom":"x","targetTo":"y"}]

Query

db.collection.aggregate({$match:{$expr:{$and:[{$eq:["$appId","1"]},{$or:[{$in:["$targetFrom",["a","c"]]},{$in:["$targetTo",["a","c"]]}]}]}}})

Result