By default, Skype for Business maintains copies of all of your Skype for Business-based interactions. To see a list of recent ones, do the following:
Open Skype for Business, and, above the search box, click the Conversations icon.
In the display, you’ll see a chronological listing of your 100 most recent incoming and outgoing instant messaging conversations (IM), audio calls, video calls, and Skype for Business Meetings, including conversation requests you might have missed. You can double-click any interaction to try to resume it.
You can change the category of information you see on the Conversation tab, by clicking either of the other two filters:
Missed Shows your 100 most recent missed conversations
Calls Shows your 100 most recent incoming and outgoing audio and video calls
If you use Outlook, you can click the View More in Outlook link, at bottom of the conversations window, to see a complete listing of your interactions.