Stories at Kendis boards are the ones that are linked to the features. In case, stories don't have their relevant Feature/Epic on Kendis board or they are not linked then stories won't appear on Kendis board sprint.
This often leads to a situation where sprint load (sum of story points) is different in AzureDevOps and Kendis.
With Compare AzureDevOps sprint option, Kendis will show you the contents that are both in Kendis and AzureDevOps sprint and the ones that are only in Kendis or only in AzureDevOps sprint. This way it would be easier to identify the gaps.
To run the comparison follow these steps
Go to a team area
Click on the 3 dots next to the sprint name
Select option "Compare Azure Sprint"
It will take few seconds to compare both Kendis and AzureDevOps sprints and results will be visible.