<p>Nuclear factor kappa B (NF-κB) has been extensively investigated for approximately four decades. Throughout this timeframe, significant progress has been accomplished in determining the structure, function, and regulation of NF-κB; however, some nuanced complexities of this fundamental signaling pathway remain underexplored. A notable gap exists in the spatiotemporal regulation and molecular dynamics of NF-κB nucleocytoplasmic shuttling, which significantly impacts the complex function and behavior, yet lacks comprehensive characterization. The nucleocytoplasmic shuttling process is also related to resistance mechanisms that evolved following the application of NF-κB or proteasomal inhibitors. Furthermore, the NF-κB complex has a stochastic variability in its trafficking that contributes to heterogeneous cellular responses at the single-cell level and lacks a well-defined druggable pocket, making its complete suppression in cancer cells challenging and uncertain. Engineering synthetic gene circuits and utilizing optogenetic tools can pave the way for precise control of the NF-κB complex, enabling advanced investigations into NF-κB regulation and post-therapeutic behavior implicated in cancer resistance. This approach also permits tumor microenvironment (TME)-immune modulation by synthetic gene circuits that reactivate immune cells within the TME. In this review, we discussed the structure and function of NF-κB, the molecular dynamics of NF-κB nucleocytoplasmic shuttling based on established findings, NF-κB engineering via synthetic biology tools, and critically deciphered the post-therapeutic behavior of NF-κB in cancer, supported by potential therapeutic targets to abrogate resistance.</p>