Complex sentence: The South Korean hip hop group iKON held their first concerts under the name "SHOWTIME" in South Korea, then they has embarked on two concert tours (iKONTACT 2014 and iKON JAPAN TOUR 2016) and all of it were in Japan.
Split into simpler sentences: The South Korean hip hop group iKON held their first concerts under the name "SHOWTIME" in South Korea. Since then, they have embarked on two concert tours (iKONTACT 2015 and iKON JAPAN TOUR 2016) both held in Japan.