Is the LG UltraFine 4K compatible with my MacBook Pro?

Hello!

The short answer to your questions is no, the display will not be compatible with your MacBook. At the link below you can find information pertaining to the Macs that are compatible with the display.

Use the 23.7-inch LG UltraFine 4K Display with your Mac or iPad Pro: https://support.apple.com/en-us/HT210105

Let me know if this helps!

I spoke with Apple Support at my Apple Store. She showed me a black "trashcan" MacPro (2013) connected to the LG UltraFine 4K Display using the Thunderbolt 3 to Thunderbolt 2 adapter. It worked fine. So I purchased the display. Here you'll see images of this working. The Mac must be plugged into power as well as the Display because there's no power supply going from the Thunderbolt 3 port on the Display to the Thunderbolt 2 port on the Mac.

Dear GSTRIB5: I'm not sure about your response. The document you reference (HT210105) has this last bullet point under System requirements and compatible Mac Models: "Mac computers with Thunderbolt 2 ports using the Thunderbolt 3 to Thunderbolt 2 adapter." I also have a 2015 15" Macbook Pro which has two Thunderbolt 2 ports right next to the the power input port. Using the adapter one would not expect the monitor to charge the Macbook, but perhaps the display can be used. I would love to hear from someone who has tried this.