Thank you for your question and picture. Pictures are very helpful for us to help you. Is your yew on the south side of your home? If so, they are very susceptible to winter burn, even on the inside of the evergreen. We also had a drought the last two years which stressed many plants, including yews, and that will also add to the yellowing of the foliage. I would lightly prune your yew now, but not to the yellowing foliage and see if it sets off some new growth. Just take a small amount. If you see new growth right now, I would wait and not prune. Here's an excellent article on winter damage to evergreens:

https://extension.umn.edu/yard-and-garden-news/winter-damage-evergreen-trees-and-shrubs

I would also water your plant well (1 inch per week), unless rain provides this amount.