S4B works in conjunction with its Toast or pop up notifications Feature, gets its data from several sources to display CallerID Information from:
1. Carrier - This is the caller's carrier and what they are providing
2. S4B Client App - This is comprised of Favorites and recent contacts as well the S4B client contact list
2. Outlook/Exchange - The contact databases from these sources
3. O365 SharePoint/Azure AD/Client Local AD - These contact databases help but aren't the main source
The consistency of caller ID data being passed to Skype for Business from carriers or other sources does impact the CallerID displayed output.
We have not found a consistent way to link the incoming call to the SharePoint contact.
The only consistent way we have found to have the full contact data show for incoming mobile
calls were to add a contact to Outlook / Exchange with the contact data.
Once we added the contact, incoming calls from cell phones showed the contact's picture and other contact data.
This also enabled the incoming call data to show on the Skype for Business mobile client.
Without the individual contact creation, incoming calls showed as described earlier -
with Caller ID / Share ID data showing per carrier (when available) or just showing the incoming phone number regardless
of contact format (E.164 or otherwise).
Adding the numbers to SharePoint, Azure AD, or the local CT950 Active Directory did not reliably show the incoming call with the full contact details.