Well CRM is kind of undetermined beast. Tryton has some tools that you can link to CRM:
- Contact book with the party module
- Relation between parties with the party_relationship module
- Leads and opportunities with the sale_opportunity module
- Customer complaint with the sale_complaint module
- Notification with the notification module
Of course it covers only a subset of all the features that could be under CRM.
There are already new modules coming that will complete the list: