To put a compression policy into effect, you must bind it either globally, so that it applies to all traffic that flows through the Citrix ADC, or to a specific virtual server, so that the policy applies only to requests whose destination is the VIP address of that virtual server.
By default, compression is disabled on the Citrix ADC. You must enable the feature before configuring it. You can enable it globally so that it applies to all HTTP and SSL services, or you can enable it just for specific services.
https://docs.citrix.com/en-us/citrix-adc/current-release/load-balancing/load-balancing-advanced-settings/enable-compression-on-service.htm