In this talk, I will discuss the role of Wilson loops in supersymmetric gauge theories, highlighting their significance as operators that preserve a subgroup of the superconformal group. I will explore various applications of these operators in both 3 and 4 dimensions, focusing on how they serve as defect conformal field theories with intriguing properties. Additionally, I will examine the renormalization group (RG) flows that connect these defect theories, providing a deeper understanding of their behavior across different energy scales.