How to include arguments to application calls in inner transactions

I want to add arguments to the application call in PyTeal:

        Seq(
            InnerTxnBuilder.Begin(),
            InnerTxnBuilder.SetFields({
                TxnField.type_enum: TxnType.ApplicationCall,
                TxnField.application_id: Global.current_application_id(),
                TxnField.on_completion: OnComplete.CloseOut,
                TxnField.sender: Txn.accounts[1]
            }),
            InnerTxnBuilder.Submit(),
            Int(1)
        ),

I want to add application_args to the transaction. Would this be an array of bytes?

You currently cannot make inner application call.

Does the foundation have any plans to make inner application calls in the future?