Joining copper with stainless steel (SS) is essential due to their complementary properties. Copper’s excellent thermal conductivity and SS’s robustness and high mechanical strength create joints that manage heat effectively and maintain structural integrity. This combination is particularly beneficial in heat exchangers, fusion reactors, electronics, batteries, chemical processing, and nuclear engineering, where efficient heat management and corrosion resistance are critical. However, the heterogeneous nature of these materials presents challenges such as differing melting points and thermal expansion coefficients. Deep understanding of metallurgical processes is needed to overcome these issues. Successfully joining copper and SS via well-established fusion welding processes can lead to innovative industrial solutions, enhancing performance, reliability, and durability across various applications. This article reviews fusion welding techniques for joining copper to SS, highlighting the need for precise parametric optimization. It identifies research gaps and emphasizes innovative welding methods to enhance joint quality, supporting advanced, reliable structural component development.