We can use the proxy pattern to solve several problems, but I find that I mainly use this pattern to solve two problems.
The first problem that I use the proxy pattern to solve is when I want to create a layer of abstraction between a single API and my code. The API could be a local or remote API, but I usually use this pattern to put an abstraction layer between my code and a remote service. This will allow changes to the remote API without the need to refactor large portions of the code.
The second problem that I use the proxy pattern to solve is when I need to make changes to an API, but I do not have the code or there is already a dependency on the API elsewhere in the application.