Where I work we have TFS but don't connect it to PowerBuilder. We have PowerGen running nightly and copy fresh PBL files to our laptops in the morning. Work in progress is stored in 'Work PBLs'. We manually import/export objects between the work PBL and a local copy of the TFS branch. We use Visual Studio to do a Get Latest Version of the local TFS branch and to do check-in.
I understand that your TFS repository can be changed to GIT format which allows you to use the GIT interface built into PB 2019.
Another possibility, configure PB 2019 to use GIT and then use these command line tools to keep your local GIT repository and the TFS server in sync: