Throughout this series, Wu Bi and Su Yu have been pretty physically affectionate, short of actually kissing. Now, the sort of physical affection they showed would clock as romantic to you and me; but I've seen others point out that in East Asia this sort of physicality is common among male friends, so it wouldn't register as romantic to an Asian audience.
However, the latest episode decisively placed the series in the BL category rather than the "bromance" one, because we actually got two kisses between them, albeit on the cheeks but that's still more than what we get out of other Chinese BLs. And in all the arguments I've seen about this series, I don't think anyone has said, "well ackshually, male friends in China kiss each other all the time."