Salamu alaikum.

Muhammad Hasan al-Istahbanati wrote in his book “Noor al-Ayn” (p 21-22; hadith 6):

Translation:

From Haroon ibn Harajat: I asked Abu Abdullah (alaihi salam): I asked him about the one who abandoned visitation of grave – grave of Hussayn ibn Ali, without any reason? He answered: He is from inhabitants of the fire.

So this makes visitation of grave of Hussayn wajib in the view of shias, and the one who doesn’t visit it, would be in the fire.