Desert
K finds Deckard in a city that has been turned to orange ash after the nuclear war. This dystopian desert is a symbol of how all great structures built by man are hollow and lifeless in the reality of war. They no longer hold value as they can no longer harbor life.
Connection
K is approached by the beautiful hologram he keeps with him that tells him he is lonely. In this advanced and "sophisticated" world full of every choice imaginable, we see that this is a symbol of the lack of true connection in the world. We will always be lonely when we are removed from truly connected with another human being.
Kill or be Killed
K is a replicant tasked with destroying rogue replicants. This is a symbol of how man turns one against its own in order to maintain power for the select few. K represents that many who make their survival by doing things for an establishment they don't believe in, because without doing this work they wouldn't have the means to survive.
Born
Throughout the film we learn more about the ability for a replicant to reproduce life rather than be created. Deckard and Rachael having a child is a symbol of the ability for replicants to reproduce, something that has never happened before. And Wallace wants to harness this power in order to populate worlds and expand his power.
An Offer
Wallace offers Deckard a clone of Rachael in exchange for all that he knows. Deckard refuses and Wallace destroys the clone. This is a symbol that what Wallace was offering Deckard was never going to be his. It's Wallace's way of showing that he controls life, he gives it and takes it.
