It's written here Word Sense Disambiguation: A Structured Learning Perspective:
2.1 Basics of Word Sense Disambiguation
...the POS is usually provided before WSD. POS tagging is closely related to WSD, and POS tagging is a well-studied problem with accuracy over 95%, thus the separation of POS tagging from WSD can fully expose the hardest core of WSD.
The best explanation for the proposition in boldface inside the blockquote I could find on google is the following picture on book Neural Representations of Natural Language:
Nonetheless, that book explain the relationship between POS tagging and other word sense problems and not to Word Sense Disambiguation.
Please, explain the relationship between POS (part-of-speech) tagging and WSD (word sense disambiguation).