Combo nanocellulose presents a promising avenue for enhancing the sustainability and performance of cementitious materials. This review explores the potential of Combo nanocellulose as a green additive in cement, focusing on its ability to improve mechanical properties, durability, and environmental impact. The unique characteristics of different nanocellulose types, such as cellulose nanocrystals (CNC), cellulose nanofibrils (CNF), and bacterial nanocellulose (BNC), are manipulated in combination to create superior reinforcement effects. These effects include enhanced tensile strength, reduced shrinkage, and improved crack resistance. Furthermore, the addition of Combo nanocellulose contributes to a significant reduction in the carbon footprint of cement production, aligning with the goals of sustainable construction. Life Cycle Assessment (LCA) studies highlight the environmental benefits, including reduced energy consumption and lower greenhouse gas emissions. This review critically examines the production methods, synergistic effects, and practical applications of Combo Nanocellulose in construction, providing insights into its potential to revolutionize the cement industry. Overall, Combo nanocellulose emerges as a sustainable, efficient, and economically feasible solution for developing nextgeneration green cementitious materials, paving the way for more resilient and environmentally friendly infrastructure. The potential challenges of utilizing CNC in sustainable construction include its susceptibility to moisture, which can compromise structural integrity, and the high energy demands associated with its extraction and processing. Additionally, scalability and cost-effectiveness remain critical limitations, hindering widespread adoption in the building materials industry.