Both of them are with Hu Yitian as the lead, their plots are about sports, though different ones, and there's romance.

*Go Go Squid 2 is not exactly a sequel to Go Go Squid 1 (which I love and I think is way better), the story is with the same characters, but a lot is different, so you do not need to watch the first one to understand the second (in fact, if you have watched the first, and loved it, do not watch the second). BUT if you have not seen GGS1 yet, and you are looking for a fluffy, cute romance with sports themes, GGS2 is a good option.