Hello Jie Yin
Welcome to Microsoft Q&A Platform, thanks for posting your query here.
Azure Cloud Services is a platform that allows developers to build, deploy, and manage applications on a highly available and scalable cloud infrastructure. It includes Cloud Services (extended support), which is a legacy offering that provides a platform for deploying and managing cloud applications.
Regarding your question, if you are using Azure Virtual Desktop host pool resources, you may need to take additional steps to ensure that your desktop (session host) can access the internet after the retirement of default outbound access for VMs. You can use a NAT gateway or Azure Load Balancer to provide explicit outbound access for your session hosts.
Alternatively, you can use Azure Firewall to filter outbound traffic and provide extra protection for your Azure Virtual Desktop host pool. You can follow the guidelines in this article to configure Azure Firewall to allow outbound Azure Virtual Desktop platform traffic.
Hope this helps.