Asus may launch Zenfone 3 in May 2016 which will come with a fingerprint sensor. If it comes then the Zenfone 3 will be the first device to get fingerprint sensor in Asus smartphones.
The fingerprint sensor which will be integrated in Zenfone 3 are developed by Taiwan-based Elan Microelectronics and China-based Goodix companies. The Asus has worked really well in past 2 years in smartphone world. In 2015 they have provided almost 20 million smartphones and in 2016 they are expecting to make it 30 million.