Density functional theory (DFT) has become a cornerstone of modern chemistry and materials science due to its computational efficiency and reasonable accuracy. However, it still faces significant challenges, including limitations in handling strongly correlated systems, accurate prediction of electronic excitations, and reliable treatment of van der Waals interactions. Recent progress has improved DFT's ability to predict properties of materials and catalysts, with functionals like B3LYP and PBE becoming widely used. Despite these advancements, DFT remains limited in its accuracy for certain systems, such as those with strong electron correlations or large gaps. Ongoing research aims to address these issues through new approximations, including meta-GGA functionals, hybrid functionals like HSE, and range-separated methods. Additionally, challenges in calculating electronic excitations and improving the treatment of weak interactions, such as van der Waals forces, remain significant. The field continues to evolve, with new methods and theoretical insights aiming to enhance the accuracy and applicability of DFT.Density functional theory (DFT) has become a cornerstone of modern chemistry and materials science due to its computational efficiency and reasonable accuracy. However, it still faces significant challenges, including limitations in handling strongly correlated systems, accurate prediction of electronic excitations, and reliable treatment of van der Waals interactions. Recent progress has improved DFT's ability to predict properties of materials and catalysts, with functionals like B3LYP and PBE becoming widely used. Despite these advancements, DFT remains limited in its accuracy for certain systems, such as those with strong electron correlations or large gaps. Ongoing research aims to address these issues through new approximations, including meta-GGA functionals, hybrid functionals like HSE, and range-separated methods. Additionally, challenges in calculating electronic excitations and improving the treatment of weak interactions, such as van der Waals forces, remain significant. The field continues to evolve, with new methods and theoretical insights aiming to enhance the accuracy and applicability of DFT.