I find a question bearing two tags and having two votes to close it.
I go to the review queue and "filter" the search to include only questions bearing those two tags. The queue turns out to be short, and that question isn't there.
Two complementary options are:
As suggested in a comment by Surb it could be that it is not yet inside the review queue due there being a 15 minutes delay (after the vote or flag), see for example this answer).
It is already through the queue that is the review was completed yet the question not closed. Note that close-votes take same time to age away even after the review was completed. This would be visible from the timeline though as you could find a link to the review-report there.
There may be other scenarios I am not aware of but this is what comes to mind.