。
I'm going to Tokyo next week.
Literal
Next-week Tokyo [to-に] go [ことになっています] (it-is-arranged-that).
~ことになっている marks an established arrangement, rule, or scheduled fact — 'it's arranged that / it's the case that.' Different nuance from ~つもり (personal intention) or ~予定 (schedule): ~ことになっている frames it as externally or collaboratively decided. Common in business/formal contexts.