CU Cancri_85cm_UBV.csv——Log of UBV-band photometric observations of CU~Cnc obtained with the 85-cm telescope at Xinglong Observatory.Columns are: (1) file name of the U-band image; (2) observation time in UTC for the U band;(3) normalised flux in the U band; (4) uncertainty of the normalised U-band flux;(5) file name of the B-band image; (6) observation time in UTC for the B band;(7) normalised flux in the B band; (8) uncertainty of the normalised B-band flux;(9) file name of the V-band image; (10) observation time in UTC for the V band;(11) normalised flux in the V band; and (12) uncertainty of the normalised V-band flux. Flares_Parameters.csv——This table summarises the parameters of 532 flare events detected on CU Cancri. Columns are: (1) event index; (2)–(3) flare start and end times. All flares were detected in Kepler/K2 data and are given in Kepler spacecraft time (BKJD = BJDTDB − 2454833), in units of days. Flares 1–520 were identified from the short-cadence data, whereas flares 521–532 were identified from the long-cadence data. (4) equivalent duration (ED), in seconds; (5) flare amplitude, in relative flux units; (6) flare duration, in days; and (7) estimated bolometric flare energy, in erg. For the long-cadence flares (Nos 521–532), bolometric flare energies were not calculated, and the corresponding entries in column (7) are therefore left blank.