MediaTek's first 5G modem, the Helio M70, is expected to be in devices in the first half of 2019, says company's CEO. But the company is working on an integrated 5G chipset as well, this one will arrive later - near the end of the year, meaning that the first devices with it should arrive in 2020. The M70 is a standalone modem - meaning it's not part of a chipset. That works quite well for MediaTek's ambitions to supply 5G modems to Apple as iPhones use external modem chips (provided by Intel most recently). Qualcomm's 5G modems are external too. A modem integrated into the chipset...
Source: https://www.gsmarena.com/mediatek_is_working_on_a_5g_chipset_coming_late_next_year-news-34024.php