There is no search. But you can filter by keywords to get what are effectively search results. Filtering is a better approach than searching as it also enables you to filter by when a card is due, who it’s assigned to, and which bucket it’s in.
Planner provides an iCal feed which can be pulled into an Outlook calendar to show as Meeting items. So, if you like using Outlook to manage your time and tasks, you can use this feed to show cards based on their start and due dates. And if the items in Outlook could be coloured (perhaps by bucket or label), then the Outlook calendar would start to be a bit roadmap-y.
Checklist items into cards
Items in a checklist can be promoted to cards by clicking on the up arrow that shows when you hover over the checklist item. The card is created in the same bucket as the card with the checklist but has no associated attributes such as due date, status or assignee. An improvement on this might be being able to choose to copy and/or set the attributes from the parent card when promoting the checklist item rather than having to go into the card after it has been created.