IoT applications normally involve heterogeneous integration of MCU, RF, sensor chips and discrete components, with the diversity but smaller quantity. PCB prototype is the first practical and cheap proof-of-concept (from 0 to 1) assembly using available package-ICs, components for initial functions test, software development and market trials, although with lower entry-barrier without much differentiation. SiP (system-in-package) is the next rationale revision option (from 1 to 2) for not only decent structural scaling, but also for system-level PPA (performance, power, formfactor and total cost) co-optimization, especially for the value-added sensor fusion, edge IoT2.0 applications or so called AIoT transformation.Such attempt of PCB migration to SiP options is not trivial to-be LEGO-like flows or simple ROI justification, if without deeper domain knowledges and chiplet design flow insights. Traditional SOC mindsets may be not sufficient, due to lacking system-level PPA(performance, power, area) considerations and more, such as thermal, stress management, decent what-if analysis and meaningful design-technology co-optimization among various structural stacking options. Some heterogenous cases are discussed in this article about IP/chip/package strategy, and potentially are developed for decent application-driven interposer platform technology proposals.