Cloudformation is infrastructure management, not configuration management. Both Ansible and Cloudformation can be used for both in different ways, but usually you have your configuration management (such as docker containers) in one step of your pipeline and cloudformation templates as another. That way you can test your infrastructure (by deploying cloudformation templates and tearing them down) as well as your code without them being too dependant.
This infrastructure/configuration distinction is very hazy when it comes to services like Lambda or Fargate, where you just specify your code artifact and there's essentially nothing more to do. It's not clear that it's a net benefit to introduce additional tooling beyond CloudFormation/Terraform for deploying to these services. It's certainly not strictly necessary.
