You can use this package in github: https://github.com/majd/ipatool

ipatool download -b com.cisco.anyconnect

You can use ipatool to download ipa files from appstore.

Requirements

macOS 10.11 or later.
Apple ID set up to use the App Store.

github: https://github.com/majd/ipatool

install ipatool on mac:

brew tap majd/repo
brew install ipatool

first you need to login:

ipatool auth login

then you need to purchase a bundle to be able to download it:

ipatool purchase -b com.cisco.anyconnect

then you can download the bundle:

ipatool download -b com.cisco.anyconnect