The 2 airlines will increase their presence in Greece next year. Condor and Lufthansa have both scheduled additional flights to the Greek islands for Summer 2020.

In summer 2020, there will be five new services helping to connect travelers to one of the most popular summer destinations in Europe. Both Lufthansa and Condor announced in November that they will offer flights to a number of Greek islands in order to meet demand in the coming summer
Condor is offering its customers direct flights to Santorini, Mykonos, and Samos starting from 1st May 2020. The airline will fly once a week to Mykonos from Düsseldorf, Frankfurt and Munich airports and will fly twice a week to Santorini.
Lufthansa will be operating its flights out of Frankfurt and Munich. The airline has plans to add Rhodes and Zakynthos to its network, starting in April 2020. Initially, it will fly both services once a week but as demand increases, so will the services.

Both airlines already have a substantial Greek offering, so why are they continuing to invest in Greece? Well, both airlines are guaranteeing themselves a busy summer.
The Greek islands have consistently been top vacation destinations and these German airlines are profiting from them.