This is the monumental tomb of Lyciarch Marcus Aurelius Archepolis in the North Necropolis. It is dated to the second half of the 3rd century AD. There used to be a vault covering the tomb (collapsed) and three sarcophagi inside, one, the Sidamara sarcophagus, is now in the Antalya museum.

You can find the area on some pictures using View Map.

A helpful source was On the Lycian Way, a book sold at museums in the area.