Just FYI . . . 5 pin DIN sockets on a synth are the *original* MIDI standard port.

If you want to connect a MIDI controller (keyboard) that has only a USB port, to your synth, you will need a MIDI HOST.

Generally, a computer running a DAW or other MIDI enable software will act as your host, but you can also get standalone hardware boxes called MIDI Hosts. You send a USB cable from your MIDI keyboard to the Host and then a pair of 5 pin DIN cables from the host to your synth...

[Here's the sort of thing...](
https://www.amazon.com/Miditech-USB-MIDI-Host-Interface/dp/B07B8XGD16/ref=asc_df_B07B8XGD16/?tag=hyprod-20&linkCode=df0&hvadid=416762403045&hvpos=&hvnetw=g&hvrand=14235945865379304699&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9015280&hvtargid=pla-728129027924&psc=1&tag=&ref=&adgrpid=89137544810&hvpone=&hvptwo=&hvadid=416762403045&hvpos=&hvnetw=g&hvrand=14235945865379304699&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9015280&hvtargid=pla-728129027924)

You can do

There are plenty of MIDI keyboards that has both USB and 5-pin DIN MIDI.

How to connect usb midi keyboard to a synth