Light curves and hardness ratio of Cyg X-1 from observations in May (left) and June (right) 2022. Panels (a), (b), and (c) report the light curves from IXPE, NuSTAR, and NICER observations, respectively; panel (d) is the hardness ratio of IXPE. The time binning is 75 seconds for all of them. The shaded time intervals highlight periods when the IXPE hardness ratio was persistently elevated, identified via a sliding-window analysis with a threshold of 2.0 standard deviations above the mean (see the text).