The new Apollo iOS Client 1.0 offers an improved approach to code generation, removing dependencies on Typescript and NPM, rewriting the tooling in Swift, and increasing runtime performance. The client generates type-safe models for GraphQL operations and fragments, providing a simpler way to construct fragment objects from generated data objects and improving data validation. A new Codegen CLI streamlines the process of running code generation, allowing users to initialize a configuration file, fetch their GraphQL schema, and generate code with ease. The client also includes features such as improved syntax for GraphQL nullability and a reduction in overall generated code size and complexity.