Mr. Khisombi holds an ADMA from IDM Mzumbe,1999, Diploma in Divinity from SDA- Morogoro Bible Collage 1983 and Master of Business Administration from Mzumbe University, 2008. Mr. Khisombi currently serves as Director of Procurement and Supplies of Public Service Social Security Fund and represents the Fund in the Board. Mr Khisombi also serves a Reverend at Tanzania Mennonite Church at Mkuhungu Healing Center-Central Dodoma Diocese.Previously, he held several positions with NSSF as Principal Procurement Officer from 2018 to 2019, Senior Procurement Officer with Musoma MC, Bunda Dc from 2017 to 2018. Head of Procurement Management Unit with Morogoro DC and Kongwa Dc from 2007 to 2017, Assistant lecture at SAUT- Mtwara Campus 2013. He is a member of the TICL Audit and Risk Committee.