I don't follow this in detail, but from what I have read the Gripen has a strong dogfighting ability and older versions have done well against the F-16 and F-15. The latest E-version is probably much better. As someone who has just read some news articles and do not have any military experience, it seems to me that it could be filling in some capacities that the F-35 is not designed for.

The E-version of Gripen was designed with NATO operability in mind, so it is probably not hard to integrate.