There were many cities in the League, but only Hamburg is still a separate political entity.
Following the dissolution of the Hanseatic League, most cities became too weak to defend themselves and were assimilated into the larger nations. This process was hastened by the dissolution of the Holy Roman Empire in 1806, meaning there was no Emperor left to protect the free cities.
Frankfurt am Main was also an independent city until it was conquered by Prussia in 1866.
However, an alliance of three cities tried to keep the Hansa going. These were Bremen, Hamburg and Lübeck. These cities remained their own states. But the Nazis revoked the independence of Lübeck in 1937 order to have an easier administration of the territory.
Bremen and Hamburg are still their own political entities now and the only free hanseatic cities where the title actually means something and is not purely decorative.
The same applies to Bremen, which is also one of Germanys "city states".
It should be noted that former Hanseatic citis still carry a "Hansestadt" or "Freie Hansestadt" in their official names. An example: Hamburg is represented as "HH" on license plates, which stands for "Hansestadt Hamburg".
Bremen is also a city state.