SameSite prevents the browser from sending this cookie along with cross-site requests. The main goal is to mitigate the risk of cross-origin information leakage. It also provides some protection against cross-site request forgery attacks.
Caching stores information that is requested by many clients in memory and serves this information as the results to client requests. While the information is still valid, it can be served potentially millions of times without the cost of re-creation.