How do you deal with stateful services when you're working with stateless microservices?

Hey everyone, I'm wrestling with a common challenge in microservices: managing state. We're aiming for a stateless architecture where possible, but some services just have to hold onto state, right? Like user sessions or shopping carts. What have you guys found works well for this? Are you using outside stores like Redis or maybe a dedicated state management service? I'm really curious to hear your real-world approaches and any traps you've run into.