On the one hand, you have Toyota - a company with a long and solid history of automotive manufacturing and arguably the pioneer of mass-market hybrid vehicles. On the other, you have Geely - the fast growing automotive company that knows a good thing when it sees it - case in point, Volvo cars. According to Reuters, there are rumours of the two companies being in talks for co-operation of gasoline hybrid electric vehicle technology - a little like BMW's partnership with Toyota.
The reality of doing business in China is that you need a Chinese business partner, and Geely is a great partner to have. With Toyota trying to ramp up sales in a market that is fiercely loyal to their local brands (and Volkswagen), Toyota is going to need all the help it can get. So far, the scarce information about this potential partnership ties to a mutual battery supplier that both companies share, although the specifics are still unknown.
Toyota has been producing hybrid vehicles in China for a couple of years now, selling them since 2015, and they plan to sell plug-in hybrid variants of the Corolla and Levin (yes, they're still using that nameplate in China) next year.