Complex sentence: Some believe that the Tangzhuang (i.e. Qipao and Cheongsam) has had a tremendous influence overseas and that many foreigners recognise them as the "de facto" Chinese national costume and that Hanfu does not share the same influence or recognition in today's environment.
Split into simpler sentences: Some believe that the Tangzhuang (i.e. Qipao and Cheongsam) has had a tremendous influence overseas and that many foreigners recognise them as the "de facto" Chinese national costume. According to them, Hanfu does not share the same influence or recognition in today's environment.