Jesus is God Jehovah is denied by some groups who claim to follow the Bible.
John 1 - 1 In the beginning was the Word, and the Word was with God(Theon), and the Word was God(Theos). 2 He was in the beginning with God. 3 All things were made through Him, and without Him nothing was made that was made. 4 In Him was life, and the life was the light of men. 5 And the light shines in the darkness, and the darkness did not comprehend it.
Some who deny Jesus is God Jehovah will argue that the first usage God = Theon - (see all the usages at http://biblehub.com/greek/theon_2316.htm) is God Jehovah, and the second God = Theos - http://biblehub.com/greek/theos_2316.htm refers is the generic term for "god" that is used to describe other gods. However if you look at all the cross references for Theos at the link above, it is obvious that it is used extensively (over 1000 times in the New Testament) for God Jehovah.
The Jehovah's Witness followers take the perspective that since in the Old Testament, it says that God is one God, that Jesus cannot be the earthly manifestation of God Jehovah, and then drive their translations of New Testament Greek in a manner of systematic theology to fit this perspective. Here is the case made in the Watchtower, a Jehovah's Witness publication, which holds their core teachings https://wol.jw.org/en/wol/d/r1/lp-e/1101989276?q=god&p=par
Reference Reading
REDI-ANSWERS ON J.W. ::DEITY OF JESUS , MISTRANSLATIONS, GOD AS FATHER SON HOLY SPIRIT
Audio
https://www.blueletterbible.org/audio_video/martin_walter/jw/How_to_Witness_to_Jehovah_s_Witnesses.cfm#Jehovah_s_Witnesses_and_the_Real_Jesus_Part_1