Liv Tyler has been out of the MCU game for around 9 years now. Her last stint had her turn up in The Incredible Hulk, and since then she has been MIA in lore.
Well that could be changing. Scottish paper Daily Record UK (via MCUExchange) seem to have nonchalantly stated that Tyler is going to be in Avengers: Infinity War. Just popped into a sentence towards the end of the article celebrating the film's shooting in Scotland, it states plainly she's 'reportedly' been lined up for a role.
Now, take this with a big grain of salt. This could just be a simple mistake on the outlet's part. We will have to see on this one.