Clearly in the cruise, pitch and power are set and not changing and common sence would dictate not changing anything (ie maintain pitch and power).
It is for an unrecognised air data malfunction where the aircraft is now probably no longer at the correct pitch or power, cruise is probably the easiest one to spot it'll be the climb or descent where the A/P or F/D has gotten the aircraft in an excessively high or low nose attitude for the phase of flight chasing an unreliable speed for example.
757 crash "349kts" 15deg nose up, max thrust, and then reduced thrust to idle and pitched up to 18deg, by the A/P. It stalled.
727 crash 405kts climbing 6,500fpm FL230 Capt "no pull her back let her climb" stall warning / overspeed warning F/O there's Mach buffet, both agreed pull up, aircraft stalled descended 24,800' in 83 sec.
after a pilot's startled reflex reaction to an overspeed alarm sent an Air France Airbus A340-300 into a rapid climb, unnoticed by the crew.