The story of Black Ops 3 is somewhat related to Black Ops 2. Some storylines and events carry over or have references that link the two. But it's not a direct continuation; there are new elements and developments too.
The story of Black Ops 4 is separate from Black Ops 3. They have different settings, characters, and plotlines. Although they belong to the same franchise, the narratives are independent of each other.
The JoJo manga is mainly in black and white. Colored versions exist but are not the norm. Sometimes, colored illustrations are done for promotional purposes or by fans.
I think it's great. The characters are memorable, the plot is full of twists and turns, and the battles are epic. It's a manga that stands out from the crowd.