Leadership from African terrorist group, Al Shabaab, met with members of Al Qaeda in the Arabian Peninsula in Yemen earlier. The evolving threat of Islamic jihad from the foundational texts have created the current future enemy, who see the West as the next target.
Al Qaeda's Third Phase by Sara Harmouch
https://mwi.westpoint.edu/al-qaedas-third-phase/
Somali al-Shabaab Fighters Reportedly Enter Yemen Amid Rising Security Concerns:
https://www.yemenonline.info/special-reports/12655