Unlike the first in which Deckard was never actually confirmed as a replicant, Goslings character is confirmed in the opening scenes. After finding out that there was a replicant child born rather than made, he starts out on a path to find out the truth.
K starts out very mechanical and it’s very obvious he isn’t human, but as you see more about his home life and relationship with Joi you start to see a different side. When he begins to believe he is the child that he is supposed to be searching out and destroying, the change is even more obvious. He starts to lie and deceive and goes in search of Deckard whom he believes is his father.
His emotions become raw as, rather like Pinocchio, he believes he is a “real boy”, important, loved and wanted. When he’s told that the child is a girl and that he was just a piece of the puzzle, he is genuinely devastated. What does it mean to be human? Dying for the right cause is one of the most human things you can do, is repeated and K sacrifices his life so that Deckard can meet his daughter.
In the moments where he lies down on the steps at the end, where you feel so sad for him, he had a dream of a life and it was dangled in front of him for a short while and it’s all taken from him.