Study of PI3Kinase Inhibition (Copanlisib) and Anti-PD-1 Antibody Nivolumab in Relapsed/Refractory Solid Tumors With Expansions in Mismatch-repair Proficient (MSS) Colorectal Cancer

Inclusion Criteria: * Age ≥18 years. * Ability to understand and willingness to sign a written informed consent document. * Phase I: Must have received all curative treatment options and at least 2 lines of systemic therapy. * Phase II: Must have received at least 2 lines of systemic therapy including a fluoropyrimidine, oxaliplatin, and irinotecan-containing regimen. KRAS/NRAS/BRAF wildtype patients must have received or refused anti-EGR. * Must have received all curative treatment options and at least 2 lines of systemic and standard therapy. * Must have measurable disease based on RECIST 1.1 * Must have biopsiable disease. * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 * Life expectancy of greater than 3 months. * Patients must have adequate organ and marrow function defined by study-specified laboratory tests within 21 days of initial study drug. * Men must use acceptable form of birth control while on study. * Woman of childbearing potential must have a negative pregnancy test and follow contraceptive guidelines as defined per protocol. Exclusion Criteria: * Prior treatment with immunotherapy agents (including, anti-PD-1, anti-PD-L1, anti- PD-L2, anti-CTLA4, etc.). * Prior therapy with a PI3K inhibitor * Chemotherapy, target small molecule therapy, investigational therapy, or surgery within 4 weeks prior to first dose of treatment. * Has received prior radiotherapy within 2 weeks prior to the start of treatment. * Patient who is receiving or hav…