Inclusion Criteria:  18-70 years old for Phase 1a, 18-75 years old for Phase 1b and 2; Histologically and/or cytologically confirmation of recurrent/metastatic squamous cell carcinoma of the head and neck; At least one evaluable or measurable tumor lesion; Adequate performance status; A minimum life expectancy of > 3 months; Adequate cardiac, kidney, and liver function; Willingness of all subjects of childbearing potential to use acceptable methods of birth control;  Exclusion Criteria:  Any chemotherapy, radiotherapy, targeted therapy, immunotherapy, endocrine therapy and other systematic anti-tumor therapies within 4 weeks prior to the first dose of the study drug (some exceptions apply) Prior or current PI3K inhibitor therapy; Type 1 or type 2 diabetes requiring antihyperglycemic medication; Major organ surgery (excluding needle biopsy) or significant trauma within 4 weeks prior to the first dose, or required elective surgery during the study period; Any unresolved toxicities from prior therapy greater than Grade 1; Inability to swallow, or serious gastrointestinal absorption conditions; History of immunodeficiency; Active central nervous system metastases; Active hepatitis B or C virus infection; Uncontrolled active infection; Serious cardiovascular disease； Clinically uncontrollable effusion in the third space; Known allergy and/or contraindications to paclitaxel; Known alcohol or drug dependence; Mental disorders or poor compliance; Pregnant or lactating women;