Check out the companies making headlines after hours.

WW International — Shares jumped more than 6% after WW International, also known as WeightWatchers, said it's acquiring Sequence, a subscription telehealth platform with a focus on chronic weight management, for a net purchase price of $106 million. The deal marks WeightWatchers' foray into a world of clientele who are taking chronic weight management medications, such as glucagon-like peptide 1s. Separately, WW International announced its fourth-quarter and full-year results.

Norfolk Southern — The stock ticked up more than 2% in after-hours trading. Earlier, a CNBC reported that Norfolk Southern is planning to make broad safety adjustments after its third train derailment.

KeyCorp — Shares fell about 2% after KeyCorp issued full-year net interest income guidance that was lower than prior guidance, according to an 8-K filing on Monday.