Long-term behavior of Cygnus X-1 measured by all-sky monitors MAXI and Swift-BAT. We follow the same approaches of state definition proposed by Grinberg et al. (2013). Upper panel: the hard, intermediate, and soft states are denoted by blue, purple, and red points, respectively. Lower panel: the unclassified and soft states are plotted with black and red points, respectively. The duration of HXMT observations on Cygnus X-1 is shown in dark orange stripes at the top.