What is してきた?
I suppose it's a conjugated form of する, but I can't find it.
I don't know if it has anything to do with this answer.
して is the te-form of する, and きた is the past form of くる. Here, くる is one of the Japanese subsidiary verbs that adds a feeling of "over a period of time (up until now)". See:
Technically speaking, subsidiary verbs like (-て)いく, (-て)しまう and (-て)みる are not part of verb conjugations. They are different verbs, as the name suggests. The conjugation list you linked does not show every possible combination of a verb and a subsidiary verb because they are not conjugations in the first place. (As an exception, the so-called "-teiru form" is on the list even though いる is a subsidiary verb. This is only for the convenience of beginners whose first language is English.)