connect 20199 MacBook Pro to Thunderbolt Display

That Mac requires the ThunderBolt available in 2011-2016, which is Thunderbolt-2.

To connect it to your ThunderBolt-3 computer with USB-C connectors, you would need this adapter:

https://www.apple.com/shop/product/MMEL2AM/A/thunderbolt-3-usb-c-to-thunderbolt-2-adapter?fnode=ef08924c4d2d4885642a96af50ca2d19ac6100a4a972b58640621d265fdc20629b7571b27c2d94102a17ed962e5422f9c66c8b56bb64cb7ef24c95c53d827062ad35305c90e89bf787fb6dede580bdf1d3873fd8f980cafb87dfc9c69a279a146a99f649e5c76b0848d50700e78c52f6

If the display has a captive cable, you are all set. otherwise, you also need a genuine ThunderBolt-2 cable.

exactly which Thunderbolt Display?