The Laniakea Supercluster contains several galaxy filaments, even just reading the wikipedia articles you provided you can see the difference in size of the two:
They are massive, thread-like formations, with a typical length of 50 to 80 megaparsecs, (163 to 261 million light years) that form the boundaries between large voids in the universe.
The Laniakea Supercluster encompasses 100,000 galaxies stretched out over 160 megaparsecs (520 million light-years).
The reason why Laniakea isn't the largest "structure" in the universe is because it inst a single object, rather an arbitrarily assigned group of galaxies. From this image below you can see how the supercluster is given an imaginary edge based on the peculiar velocities of the galaxies within it, there is no observable edge to the supercluster, unlike galaxy filaments that have visible edges.