System owner twin
At Spotify, the two camps (Dev and Ops) are overlapping in responsibilities, skill sets and interests. We have some uncommonly opsish developers here, and likewise many of our ops engineers have a strong developer background. The advantage of having this overlap is immense in the day-to-day, solving potential blockers long before they arise.
Backend services typically have two so-called System Owners - one from Dev and one from Ops. Their core responsibilities reside in their respective dominions - the dev system owner owns the code, design and architecture, while the ops system owner owns the service once life is blown into it when it is deployed and is serving traffic. However, these two areas have great overlap, and thus the two system owners have regular checkups to discuss scalability, changes is neighbouring backend topology, coming new products which will affect service behaviour, etc.