In my ADF CI/CD setup mentioned here, when I deploy to ACC or PRD after I have deleted some resources (linked service or pipeline), it is not getting deleted in ACC or PRD. But those things I add or edit are updated correctly. How can I fix it ?
I'm assuming the deployment task is set to Incremental as in your documentation. If this is the case then the deployment is doing a delta on the existing defined resources. Since the ones deleted out of your ARM template the Deployment task does not know to evaluate them. You can set it to "deployment" mode as stated in the link you provided:
Keep in mind this will delete and recreate and potentially involve some downtime while recreation occurs.
For more information check out the different Azure Resource Manager deployment modes.