https://www.cnet.com/news/samsungs-seeing-sluggish-phone-sales-too-but-its-eyeing-the-galaxy-s10-debut/

Most of its businesses -- from chips to displays -- felt the effects of stronger competition and weaker demand in the handset sector. Its smartphone sales declined, memory chips destined for handsets didn't sell as well, and its mobile displays suffered as it faced more competition. 

"Unfavorable business and macroeconomic factors led to slower performance in the final quarter," Samsung said in a press release about its earnings.