The article reviews the progress in the research of iron-based superconductors, highlighting the experimental benchmarks and unresolved questions. The discovery of superconductivity in layered iron-based materials, with transition temperatures up to 55 K, has sparked extensive research. Key questions include the role of magnetism, chemical and structural tuning, and pairing symmetry. The article discusses the crystal structures and tuning parameters of iron-based superconductors, emphasizing the interplay between magnetic and electronic interactions. It also explores the electronic structure, magnetism, and the nature of the superconducting state, focusing on the pairing symmetry. The experimental evidence suggests an unconventional pairing mechanism tied to magnetism, with a focus on the $s^\pm$ symmetry. The article concludes by discussing the challenges and future directions in understanding the fundamental mechanisms of high-temperature superconductivity in iron-based materials.The article reviews the progress in the research of iron-based superconductors, highlighting the experimental benchmarks and unresolved questions. The discovery of superconductivity in layered iron-based materials, with transition temperatures up to 55 K, has sparked extensive research. Key questions include the role of magnetism, chemical and structural tuning, and pairing symmetry. The article discusses the crystal structures and tuning parameters of iron-based superconductors, emphasizing the interplay between magnetic and electronic interactions. It also explores the electronic structure, magnetism, and the nature of the superconducting state, focusing on the pairing symmetry. The experimental evidence suggests an unconventional pairing mechanism tied to magnetism, with a focus on the $s^\pm$ symmetry. The article concludes by discussing the challenges and future directions in understanding the fundamental mechanisms of high-temperature superconductivity in iron-based materials.