Rather than trying to give an honest & detailed description of the 2 tires, I'll post two of the reviews written this year by Tire Grades, which give a fairly non biased detailed description of both tires. as well as some alternatives the site considers close competitors to both tires.
The biggest advantage I can tell from all the reviews & videos I've read & seen is the extra traction that the CC2 gives compared to the Defender2. The biggest disadvantage I believe the CC2 has compared to the Defender2 is that it has a higher rolling resistance, resulting in poorer fuel economy. There are literally dozens of reviews & vids that talk about this disadvantage with most of the comments saying they felt like the advantages (especially the excellent traction in snow & ice conditions) were well worth the minimal loss in fuel economy. The CrossClimate2 has a 640 treadwear rating, a B traction rating, and an A temperature rating. The CC2 has a 6 year, 60,000 mile warranty.
The biggest advantages I can tell from reviews & personal experience is the handling, exceptional ride characteristics, and quiet drive that the Defender2 has from other tires I've owned and from what I've gleaned from the reviews & videos I've seen on the CC2. The biggest disadvantage I believe the Defender2 has compared to the CC2 is the winter traction. The Defender2 is still rated in the 8-9 out of 10 range in most revies, but hopefully I'll be able to address just how well they handle Iowa winter weather personally by next spring. So far we've had an exceptionally warm & dry winter... The Defender2 has an 840 treadwear rating, a B traction rating, a B temperature rating, and a 6 year, 80,000 mile warranty.
As a side note I feel the need to edit this and mention that if I had known when we bought this RAV4 that they all read 2 mph faster than the actual speed I would have went up one size. Our Limited hybrid uses 225/60R18 and I would have sized up to 235/60R18s. I believe this may have given us an even smoother ride, given us a bit more protection from potholes, and would have been much closer to the actual speed. I also want to mention that my first choice for tires was the Michelin Defender LTX M&S, but that tire is not available in either one of these sizes. The Defender LTX M&S is one of the finest tires Michelin makes for a wide range of vehicles. Hope this gives you at least some of the info you're looking for.
Michelin CrossClimate 2 Review (2023) | TireGrades
Michelin Defender2 Review (2023) | TireGrades