I have a 2016 Camry.
The owner's manual says to "check" the transmission fluid at 100K miles.....no service is called for.
I took mine to the dealer had had a fluid EXCHANGE done at about 50K miles.....about $200
The tranny is pretty reliable (2016 is after the torque converter shudder issue that there was a TSB for).
Not having a dip stick or easy way to add fluid is something to get used to.
Apparently this transmission is quite sensitive to fluid level, so getting it right is important.
$200 sounds like a lot.....but every 30K to 50K (or whatever interval you may choose depending upon your vehicle usage) is not really that much when the job is done RIGHT.
There is a internal filter that IS a REAL filter, not just a nylon screen like my 2003 Sienna had.
I would guess......that in normal usage, that filter will be fine for at least 100K miles.