This work addresses the formation of microstructural heterogeneities during the laser powder bed fusion (LPBF) of CM247LC, a nickel-base superalloy with high γ′ content and hence, highly prone to weld-cracking. Multiple cracking mechanisms have been identified as active in the LPBF of various precipitation-strengthened superalloys. However, there is no precise understanding of how LPBF thermal processing conditions induce the development of specific cracking characteristics. Through a thorough revision of the literature, discrepancies in the formation and distribution of various microstructural heterogeneities were first identified. These primarily correspond to the coarsening mechanism of small γ′ precipitates, and the apparent nucleation of the γ/γ′ eutectic phase. It is proposed here that a closer examination of the development of these microstructural features can lead to new insights into the physical mechanisms driving the formation of cracks upon rapid solidification. To study the previously mentioned, a multiscale modelling framework has been cooperatively utilised to capture the influence of LPBF thermal processing conditions on the solute partitioning behaviour, which ultimately dictates the nucleation of secondary phases and the evolution of the microstructure. The integrated modelling framework (IMF) comprises three different numerical methods: (1) CALPHAD approach, (2) finite element analysis (FEA), and (3) multi-phase field modelling. CALPHAD-based models were utilised to explore how alloying additions affect the material's printability properties due to changes in phase transitions, phase-fraction evolution, and solute partitioning tendency. From this analysis, a solid-state transformation from a supersaturated γ solid-solution is proposed to better explain the inconsistent documentation of γ/γ′ eutectic, among other microstructural heterogeneities. To link thermal processing conditions with the microstructure evolution, a heat transfer analysis was performed to elucidate the thermal history induced in LPBF processing. This study delivered a more consistent description of the thermal history when incorporating the thermal conductivity, κ_tc(T), and heat capacity, CP (T), as function of temperature. The nonlinear temperature profiles delivered by this heat transfer analysis were subsequently coupled to the multi-phase field numerical framework. The coupling of a nonlinear thermal history demonstrated that no proportional correlation between the scanning speed, ν, and the induced cooling rate, $T\dot{}$, can be anticipated, as it is conventionally assumed in the 3D printing of metals. This coupling scheme delivered compelling insights into the development of various microstructural heterogeneities. These simulations were contrasted against the experimental results reported here. In the present work, the as-built microstructure, cracking characteristics and chemical analysis were examined via high-spatial resolution imaging in electronic microscopy. Particular examination was directed to regions in the vicinity of a crack feature. The solute partitioning tendency was found to be dissimilar at regions distant and close to the notch of the crack. This phenomenon was extensively discussed and compared with multi-phase field predictions. Qualitative agreement between experiments and simulations is consistent when examining the solute partitioning tendency. These results delivered a more consistent description of the development of microstructural heterogeneities and their connection to the formation of cracks.