Mid-infrared frequency combs are coherent light sources that emit a broad spectrum of evenly spaced, narrow lines with precisely measurable frequencies. These combs, originally developed in the near-infrared and visible regions, have revolutionized frequency metrology and have found applications in fields such as astronomy and attosecond science. Recent efforts are now exploring their extension to the mid-infrared region, where they promise to significantly expand the range of applications. Mid-infrared frequency combs offer improved precision, sensitivity, and spectral bandwidth for molecular spectroscopy, potentially leading to new discoveries in molecular sciences. Mid-infrared spectroscopy is valuable for identifying and quantifying molecular species due to the strong vibrational transitions of many molecules in this region. The mid-infrared region also contains atmospheric windows that allow for the detection of trace vapors with high sensitivity. Laser frequency combs have enabled precise measurements of frequency and time, and their use in spectroscopy has led to the development of optical atomic clocks and advanced diagnostic tools. Mid-infrared frequency comb generators are being developed using novel laser gain media, nonlinear frequency conversion, and microresonators. These technologies offer a wide range of repetition frequencies and spectral spans, enabling precise spectroscopy and new applications. Techniques such as difference frequency generation, optical parametric oscillation, and Kerr comb generation are being explored to generate mid-infrared frequency combs. These methods have demonstrated high spectral resolution and power, enabling applications in spectroscopy, metrology, and imaging. Mid-infrared frequency combs have been applied in precision spectroscopy, molecular diagnostics, and fundamental physics research. They enable accurate frequency measurements, which are crucial for testing fundamental physical laws and determining constants. These combs also support Doppler-free spectroscopy, allowing for highly sensitive measurements of molecular transitions. Applications include molecular clocks, trace gas detection, and the study of molecular dynamics. Future applications of mid-infrared frequency combs may extend to new fields such as ultrafast phenomena, attosecond physics, and advanced diagnostics in chemistry and biomedicine. The development of compact, high-resolution instruments based on microresonators and other technologies may further enhance the capabilities of frequency comb spectroscopy. The continued advancement of mid-infrared frequency comb technology is expected to lead to new scientific discoveries and practical applications in various fields.Mid-infrared frequency combs are coherent light sources that emit a broad spectrum of evenly spaced, narrow lines with precisely measurable frequencies. These combs, originally developed in the near-infrared and visible regions, have revolutionized frequency metrology and have found applications in fields such as astronomy and attosecond science. Recent efforts are now exploring their extension to the mid-infrared region, where they promise to significantly expand the range of applications. Mid-infrared frequency combs offer improved precision, sensitivity, and spectral bandwidth for molecular spectroscopy, potentially leading to new discoveries in molecular sciences. Mid-infrared spectroscopy is valuable for identifying and quantifying molecular species due to the strong vibrational transitions of many molecules in this region. The mid-infrared region also contains atmospheric windows that allow for the detection of trace vapors with high sensitivity. Laser frequency combs have enabled precise measurements of frequency and time, and their use in spectroscopy has led to the development of optical atomic clocks and advanced diagnostic tools. Mid-infrared frequency comb generators are being developed using novel laser gain media, nonlinear frequency conversion, and microresonators. These technologies offer a wide range of repetition frequencies and spectral spans, enabling precise spectroscopy and new applications. Techniques such as difference frequency generation, optical parametric oscillation, and Kerr comb generation are being explored to generate mid-infrared frequency combs. These methods have demonstrated high spectral resolution and power, enabling applications in spectroscopy, metrology, and imaging. Mid-infrared frequency combs have been applied in precision spectroscopy, molecular diagnostics, and fundamental physics research. They enable accurate frequency measurements, which are crucial for testing fundamental physical laws and determining constants. These combs also support Doppler-free spectroscopy, allowing for highly sensitive measurements of molecular transitions. Applications include molecular clocks, trace gas detection, and the study of molecular dynamics. Future applications of mid-infrared frequency combs may extend to new fields such as ultrafast phenomena, attosecond physics, and advanced diagnostics in chemistry and biomedicine. The development of compact, high-resolution instruments based on microresonators and other technologies may further enhance the capabilities of frequency comb spectroscopy. The continued advancement of mid-infrared frequency comb technology is expected to lead to new scientific discoveries and practical applications in various fields.