Dell monitors that start with a U are usually compatible and tested with Macs.

They are more expensive. 

You would want something like a U24xxHE  that would have a USB-C connector, but check it will work with your Mac.

That monitor won't have a speaker though.

@Andy K​ 

Hello Andy Thank you!

What is a U24xxHE? is that a connector or a monitor? Where do I get it.  I would like a speaker so maybe I should just return the monitor and buy a new one that will work? 

Verify the video port on your MacBook Pro as the older one may have mini-DisplayPort (thunderbolt) instead of USB-C (thunderbolt).  Albeit a connection from laptop USB-C thunderbolt to monitor HDMI should work.

If your MacBook Pro actually has USB-C thunderbolt and you want a matching thunderbolt monitor, you can select the monitor from here  https://www.dell.com/en-us/shop/computer-monitors/ar/8605/thunderbolt?appliedRefinements=46124

@AllcoMed​ 

U24xxHE is a monitor. (without speaker). Where xx is a year, e.g 24

But I'm not 100% sure it will work with your computer.

It has a wide range of video inputs though:

• 1 x DisplayPort version 1.4 (DRR for Microsoft Windows) (HDCP 1.4) (supports up to FHD 1920 x 1080 120 Hz)
• 1 x HDMI (HDCP 1.4)(supports up to FHD 1920 x 1080 120Hz TMDS as per specified in HDMI 1.4)
• 1 x USB Type-C upstream port (video and data) (Alternate mode with DisplayPort 1.4, Power Delivery PD up to 90 W)