Hi Marko,
All third party integrations which are supported by UCCE are supported on HCS CC. Comstice is one such partner which can be integrated and another one is 2Ring.
Refer to the links below for more details:
https://marketplace.cisco.com/catalog/companies/comstice-limited/products/comstice-uccx-ucce-wallboard
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cust_contact/contact_center/hcs-cc/10_0_1_SU1/Install_config/HCSCC_BK_I8A8633B_00_installing-and-configuring-cisco-hcs.pdf
For a complete of third party integrations/partners refer to the link below:
https://marketplace.cisco.com/catalog/search?utf8=%E2%9C%93&search%5Bq%5D=&search%5Bdeployment_model_category_ids%5D=&search%5Btechnology_category_ids%5D=24&search%5Border%5D=tier&per_page=all&pagination_page_number=1&_=1489599124162&ts=1489599133043
Regards,
Aseem Anand
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