Hello @Manal C.
Below linked page lists all environments, technologies, and versions that can be monitored with Dynatrace. This list is continuously growing, so check back often.
The Dynatrace OneAgent SDK enables you to instrument your application manually to extend end-to-end visibility for frameworks and technologies for which there is no code module available yet.
As PowerBuilder is a thick client application you most likely don't want to use a OneAgent/SDK to monitor it, but monitor it using OpenKit.
This would allow you to only license the DEM usage of the application, instead of having to install OneAgents everywhere and treat it like a server. It'd also give you session tracing instead of seeing it as services.
If you don't have the resources to write a wrapper for calling OpenKit from PowerBuilder you can reach out to our services department for help.