。
She's at the cutting edge.
Literal
She [topic-は] forefront [object-を] is-going.
先端を行く (せんたんをいく) is an idiomatic expression meaning 'to be at the forefront' or 'to be on the cutting edge.' Literally 'to go at the tip/leading edge,' it describes someone who is the most advanced or up-to-date in their field. The polite progressive ~ています marks this as her current ongoing state.