I have this idea of China being in WWI on the side of the Central Powers with Yuan Shikai on board; the POD I've thought up for this is that he decides to stay with the Qing instead of defecting in fall 1911 simply to retain his role as PM despite the risk of being disposed of which leads to the Xinghai revolution being crushed, which when leads to him enacting a coup against the Qing Dynasty in 1912, basically his Empire of China coming 3 years early. He then turns to whatever power to bolster his forces to wage war to cement his power and he gets his chance when WWI happens as we know it, albeit with provocation by Japan in 1915 in regards to the 21 Demands being fully rejected, which leads to him attacking the Entente and Japan that same year.
Thing is I'm not sure how this will go well considering my sparse knowledge of China during the 1910's, though it's something that I thought up as an excuse to have USA be somewhat more willing to be more pro-Japan than it was pre-1945 regarding the US's dissatisfaction of China in the CP and being more willing to have Japan share influence in China as part of a deal to decrease tensions between the two countries.