HI @MBilal-079 ,
Do you want to create a canvas app using CDS as data source for both Dynamics 365 CRM & Business Central?
If you want to create a canvas app using CDS as data source for both Dynamics 365 CRM & Business Central, I afraid that there is no way to achieve your needs in PowerApps currently.
Actually, the D365 CRM Entity is based on CDS Entity in same PowerApps Environment (Dynamics 365 instance), so you could use the canvas app based on CDS Entity for your Dynamics 365 CRM platform.
But the Dynamics 365 Business Central table is not built on CDS, so you could not use the canvas app based on CDS Entity for your Dynamics 365 Business Central platform.
On your side, you need to create another individual canvas app for your Dynamics 365 Business Central platform.
More details about generating an app based on Dynamics 365 Business Central, please refere to the following video:
https://www.youtube.com/watch?v=HKT6OsH2SXw
Best regards,