As one of the most significant cryospheric landforms that respond to climate warming in permafrost regions, thermokarst lakes profoundly influence ecological changes, regional hydrological cycles, and biogeochemical processes while compromising the stability of permafrost engineering. This study reviews recent advances in the formation and evolution of thermokarst lakes, their hydrological cycles, heat transfer, ecological and environmental effects, and engineering impacts across northern hemisphere permafrost regions. Research indicates that in the discontinuous permafrost zones of the Arctic, lake and pond areas show a predominantly decreasing trend, whereas, in continuous permafrost zones, both expansion and shrinkage are observed. On the Qinghai-Tibet Plateau, climate warming and increased precipitation have led to the rapid formation and expansion of thermokarst lakes. The evolution of these lakes, coupled with hydrological cycling and thermal effects, alters the physicochemical properties of the surrounding soils, influences hydrothermal dynamics in alpine ecosystems, and reduces the stability of adjacent permafrost engineering structures. Furthermore, the development of thermokarst lakes accelerates the decomposition of permafrost carbon stocks, releasing greenhouse gases such as CO₂, CH₄, and N₂O, which further feedback into the climate system. Currently, coupled water-heat-carbon cycling processes and their environmental implications represent a key research focus in permafrost science. Future studies should comprehensively consider the interactive effects of climate change and human activities and, based on coupled water-heat-carbon cycling processes, develop high-precision land surface process models to investigate ecological succession, water resource dynamics, and carbon cycling in permafrost regions under changing environmental conditions, thereby advancing cryospheric science.