Why no bismillah in surah touba?

Surah At-Tawbah (Chapter 9 of the Quran) does not begin with "Bismillah" (In the name of Allah) because it addresses themes of conflict and disavowal, particularly regarding the treaties with the polytheists of Arabia. The absence of "Bismillah" signifies a shift in tone, reflecting the urgency and seriousness of the message. Additionally, it serves to highlight the chapter's distinct nature compared to other surahs, emphasizing its focus on accountability and divine command in the context of warfare and disobedience.