Sekiro: Shadows Die Twice is a beautifully crafted game. The combination of excellent story-telling and world-building, gorgeous visuals and sound design along with an outstanding combat system will make it one of 2019's best games. The one aspect that keeps it from being a must-play for everyone is the sheer level of difficulty that some players will find off-putting.
It's going to be grindy, there will be so much loot that you won't know what to do with it, and I personally find the story a little hard to get immersed in. However, the combat is great and the mechanics work well together, there is a huge world to explore and for people who love the genre, this will be one they don't want to miss.