I know over analog, these would obviously be compatible, and I'm pretty sure that Kenwood is the only brand that uses NXDN, but Motorola is not the only brand that uses Trbo.
In simpler terms, do the Kenwood Digitals have a Mototrbo mode or is it only NXDN?
There are several companies that support NXDN and many that produce NXDN radios:
Welcome to the website of the NXDN Forum Website
www.nxdn-forum.com
Icom, Ritron, Kenwood, Alinco, Hytera….
As stated, Mototrbo has some proprietary functions that prevent 100% compatibility with any other brand. Motorola is well known for locking customers into Motorola only features.
If you look strictly at the ETSI DMR standard, Kenwood supports it.
There are several radios capable of doing it:
NX-5000 line
NX-3000 line
NX-1000 line
NX-P1000 "ProTalk" line
And then there's the older TK-Dx40 line of mobiles and portables.
In addition, Kenwood sells DMR repeaters and trunked systems.