The couldn't have:
The executive order on the tariffs on Chinese imports was signed on 11st of April, starting begin effective next day.
The announced CPI is for the entire month of April.

Most companies had immense stocks prepared before the tariffs date, all imports are less than 5% of the US GDP and some are not even making into the list that takes the CPI index, other things are taking time before being reflected in the price, going overboard with an example you import coal at 100% extra but it takes time till you use it for steel and that steel takes months before gets used in a house and that house will be ready in another half a year, so the price will reflect over a year from the actual purchase of more expensive materials.
If tariffs start to bite you won't see them sooner than 2-3 months, my nephew company for example has bought stocks for 6 months of supply  (from the US) scared that the EU might retaliate and slap US imports also.

Food and energy mainly oil was also down, US isn't importing anything from China here, and with oil down inflation will also increase less.
On top of everything else there is another thing, let's assume a t-shirt now cost 100 instead of 20, if nobody buys it it then they won't be taken into account at all since buyers will switch to 25 clothes from India.