Historically speaking, my best guess is that a new model iPad 10.2" might be in September/October.
This is the typical timeframe for release of new models for the standard iPad model.
The last two models (7th and 8th gen) were release in September.
Reference =>
https://en.wikipedia.org/wiki/IPad#Model_comparison
However this is not a given as Apple have been known to change release dates as they did in moving from March 2018 for the 6th gen to September 2019 for the 7th gen.
Additionally, we don't know what effect COVID may have on production lines in manufacturing and possible shortages of chips.