It is possible to get the information about which APARs are included in each CARS. It takes a series of steps which are documented for you here:
1- Go to http://ca.com/mainframe-cars
2- At the bottom of this page you'll see a section titled "CA RS Reports and related Tools"; the first link in this section is "CA RS for z/OS Monthly PDF Reports". Click that link. It will take you to the most recent list of all CARS that have been produced, organized by year and month.
3- Click on the CARS level that interests you. This will take you to a page of CA Products (listed by name and release) which have APARs included on that CARS.
4- Click on whichever product(s) you are interested in, and that takes you to a spreadsheet including the actually APAR names. For instance, if you clicked on CARS1609 and product CA Datacom/DB 15.0, it would show you this list of APARs: https://support.ca.com/phpdocs/0/8319/CARS1609/DCDB150.pdf
The only drawback to this is that the APARs are listed very discretely by product. Therefore, you may have to click multiple products to get all of the APARs that impact you, depending on which products you're using (e.g.: CA Datacom/DB; DA Datacom CICS Services 15.0; CA Datacom Server 15.0; etc).