Thanks for giving suggestions, and they are so helpful!
I was accepted at the BIDS (Biomedical Informatics and Data Science) track, a new program. I found researches from both the programs interest me through interviews. The primary thing I'm worried about WashU is the livability of st Louis (e.g., safety and weather).
I am an international applicant, so I will not attend the campus trip. For international students, there will be a virtual "re-visit" weekend on April 7-8. I hope I can make my decision after that meeting.