Should I pick CS & bio sciences (CSB) or pick ECE in IIIT Delhi, considering CSB is a new branch this year?

Truth be told, n=both CSB and ECE at IIT Delgi will be excellent academic decisions because IIIT Delhi is well-known for imparting quality education. You should consider your own inlciation whole choosing between CSB and ECE rather than the newness of the branch and its credibility because, at the end of the day, your interests matter more than anything. You won't be able to excel at even an old and well-established branch if you have no interest in it while may excel in a new branch if you are genuinely interested in it. So, the opportunities you will be offered depend on your passions.

You can go through the course descriptions mentioned on the institute's website. CSB might be a relatively new branch but IIIT Delhi has been offering biology courses. You can check the profiles of the faculty.

Remember, a new branch may impose certain disadvantages but so will a branch that does not intrigue you genuinely. There won't be any major difference in terms of higher studies and placements.

So, choose wisely!