When a first PDCCH candidate is capable of being used to carry first DCI, a terminal device performs, in a first cell, blind detection (BD) counting or non-overlapping control channel element (CCE) counting on the first PDCCH candidate, where the first DCI is DCI in a first format, one piece of DCI in the first format is used to schedule data transmission in a maximum of one cell, the first DCI is used to schedule data transmission in a second cell, and the first cell is different from the second cell.