Your company owns your corporate website, so Marketo would never be able to publish something to your domain.
The CNAME actually is your website, since you are responsible for adding a rule in DNS to indicate that a specific address (that you own) should actually point to one of Marketo's servers. Any request to that address would be routed by your own DNS resource record to Marketo. Because you own your DNS resource record, this is your website. Marketo has no control over what happens when a request is made to that address.
If you want to use Marketo functionality on your own website and not use a CNAME, you can manually "embed" things like tracking javascript and forms but you would not be able to leverage the rich functionality Marketo has to offer. We highly recommend you implement a CNAME so that you can use this functionality.