It's the McCall Sentinel pattern, here's a link to it on Amazon

Cosplay by McCall's M2080A50 "Sentinel" Sewing Pattern, A5 (6-8-10-12-14) https://www.amazon.com/dp/B06XP67QCB/ref=cm_sw_r_cp_apan_glt_i_KJH8D09WFQ06SY4GZG42?_encoding=UTF8&psc=1