Brentuximab Vedotin With Pembrolizumab in Metastatic Solid Tumors

Inclusion Criteria * Participants must have * Metastatic squamous or nonsquamous non-small cell lung cancer (NSCLC) (without known targetable EGFR, ALK, ROS1, or BRAF mutations) who either * a) have not yet received frontline therapy for metastatic disease and without prior exposure to anti PD-1/PD-L1 or * b) are relapsed/refractory with progression on anti PD-1/PD therapy. * Relapsed/refractory metastatic cutaneous melanoma (regardless of mutation status) with progression on a PD-1 inhibitor * Metastatic head and neck squamous cell carcinoma (HNSCC) who have not yet received frontline therapy for metastatic disease and without prior exposure to a PD-1/PD-L1 inhibitor. * Cohorts 1-4 only: Melanoma participants must be currently on PD-1 checkpoint inhibitor (CPI) therapy (e.g. nivolumab or pembrolizumab) or had their last dose of PD-1 CPI containing therapy as the last previous line of therapy within 90 days prior to enrollment; PD-1 CPI therapy must be the immediate prior line of treatment. * Cohorts 1-4 only: Participants must have progressed on treatment with an anti-PD-1 monoclonal antibody (mAb) administered either as monotherapy, or in combination with other CPIs or other therapies. PD-1 treatment progression is defined by meeting all of the following criteria. * Have received at least 2 doses of an approved PD-1 inhibitor. * Have demonstrated disease progression (PD) after a PD-1 inhibitor as defined by RECIST v1.1. * Progressive disease has b…