Hybrid modeling has gained substantial recognition due to its capacity to seamlessly integrate machine learning methodologies while preserving the fundamental physical principles inherent in a model. Although these hybrid models have predominantly been applied to temporal processes governed by ordinary differential equations, the intricacies of various real-world systems, characterized by a diverse array of physical processes, extend far beyond this domain. This study extensively investigates the application of hybrid modeling techniques within the context of a complex biological system regulated by the reaction−diffusion equation, a specific type of partial differential equation. The primary objective is to tackle the challenges associated with latent chemical mechanisms that are concealed from direct observation. The proposed approach introduces a hybrid modeling framework that synergizes neural networks with mathematical methods to estimate parameters exhibiting spatiotemporal variations within a category of problems involving dynamic boundaries. Model training is executed through a back-propagation algorithm, adept at efficiently updating these parameters while ensuring numerical stability. Subsequently, the hybrid model is employed in the context of reaction−diffusion models, yielding results that validate its proficiency in precisely estimating variable diffusivity across both space and time as well as temporal fluctuations in cell proliferation rates and cell carrying density. The mean squared error of the final output predictions by the hybrid model is 9.4 × 10 −6 as compared to that of a simple first-principles model which is 3.12 × 10 −4 .