Linked from
The 16 pages that link to CNO cycle, each with the reason it gives.
Main sequenceRelated: It dominates core hydrogen fusion in sufficiently massive main-sequence stars.
Nuclear astrophysicsBroader topic: It is a major hydrogen-burning pathway in hot stars.
Solar neutrinoRelated: It produces a smaller, distinct component of the Sun’s neutrino flux.
Blue supergiantBroader topic: It dominates hydrogen burning in the hot cores of many massive stars.