CMMi for Development: Processes

Can you see that the PMBOK processes are found mostly at Maturity Level (ML) 2 (with a few on Level 3 and above).
Also see that the Standards / Frameworks landscape: Software Engineering, DevOps, KanBan, ITIL, CM, Traditional & Agile Project Management Process, Cobit and others are fundamentally all focused on removing constraints between ML2 processes PP and PMC as you improve between baselines.
To illustrate this point for Agile Project Management check out PP and PMC for Scrum here.

CMMi-Dev1.3 dashboard