The Sponsor is developing KB707, a replication-defective, non-integrating herpes simplex virus type 1 (HSV-1)-derived vector designed to stimulate an anti-tumor immune response through the production of cytokines within the local tumor microenvironment in the lungs. KB707 is administered via nebulization, delivering the therapy directly through the airways to the lungs of subjects with advanced solid tumor malignancies. This is a Phase 1/2, open-label, multicenter, dose escalation and expansion study designed to evaluate the safety, tolerability, preliminary efficacy, and immunologic effect of KB707. Monotherapy KB707 dose escalation and expansion cohorts enrolled adults with advanced solid tumor malignancies affecting the lungs who had progressed on standard of care therapy, cannot tolerate standard of care therapy, or refused standard of care therapy. The dose escalation phase (Cohorts 1 and 2) evaluated KB707 monotherapy using a standard 3+3 design, followed by a dose expansion phase (Cohort 4) to further evaluate the selected dose. Subjects received inhaled KB707 weekly for three weeks, then every three weeks. The dose escalation portion of the study is now complete, and the selected dose is being evaluated in the expansion phase. Combination regimens with a selected (fixed) dose of KB707 are being evaluated in subjects with advanced or metastatic non-small cell lung cancer (NSCLC). Subjects in Cohorts 5 and 6 are receiving inhaled KB707 once every 2 weeks (q2w), delivered in combination with Keytruda once every 6 weeks. Subjects in Cohort 7 are receiving inhaled KB707 in combination with docetaxel once every 3 weeks. All subjects will be treated until tumor progression, death, unacceptable toxicity, symptomatic deterioration, achievement of maximal response, subject choice, Investigator decision to discontinue treatment, or the Sponsor determines to terminate the study.