DingTalk / 钉钉 / Dīngdīng is a Chinese enterprise communication and collaboration platform developed by Chinese internet provider and search engine Alibaba.
https://calendar.dingtalk.com/dav/u_xxxxxxxx/primary/ if you want to access your primary calendar directly
ID: your DingTalk username (something like u_xxxxxxxx)
PW: your password
where u_xxxxxxxx must be replaced by your username generated by DingTalk.
It seems that contacts are not offered via CardDAV.