Past Senior the career forks into two full-fledged tracks: a people track (Teamlead → Engineering Manager → Director → CTO) and a tech track (Staff → Principal → Distinguished → Fellow).
Both tracks are equally senior by impact but demand fundamentally different skills: one delivers other people's results through humans and processes, the other through architecture and standards.
The fork helps an engineer pick a track on purpose and a company build a real dual ladder rather than a 'Principal in the title' one.
Compare how the person scales impact: people and process, or architecture and standards.
Define next-level expectations without mixing the two tracks.
Build a transition plan: new skills, scope of influence, and decision types.