OnePlus' 5G phone isn't the OnePlus 7, but will use Snapdragon 855
https://www.cnet.com/news/oneplus-5g-phone-wont-be-the-oneplus-7-but-will-be-first-with-snapdragon-855/
Along with Samsung and Motorola, OnePlus is eager to announce its early attachment to a 5G carrier. 5G will gradually replace 4G LTE data speeds with an even faster connection that promises to upload and download whole movies, large photo files, games and music at a fraction of the time as your current phone.
Although the first 5G networks and phones aren't expected until mid-2019, phone brands like OnePlus are banking on customers' willingness to switch to a "future-proofed" 5G-ready device as a way to get ahead of competitors that are slower to adopt 5G.